Update docs metadata for release of `azure-keyvault-secrets`

[mccoyp]

azure-keyvault-secrets version 4.8.0 was successfully released yesterday, but the ESRP publishing stage erroneously raised an error. This caused other steps, like docs publishing, to get skipped. This PR manually updates docs metadata accordingly.

Based on updates to other KV libraries, e.g. https://github.com/MicrosoftDocs/azure-docs-sdk-python/commit/b98409e3758dafd5bed3ca1095d9aa4494dc3166

The diff displayed here is excessive because of line ending changes; here's a more accurate diff showing that the only updates are to metadata, README content updates (minimum Python version and sample link updates), and links to the Python repo (updating the release tag): https://www.diffchecker.com/ef9mbiIK/

[learn-build-service-prod[bot]]

Learn Build status updates of commit e3a41fb:

:warning: Validation status: warnings

File	Status	Preview URL	Details
docs-ref-services/latest/keyvault-secrets-readme.md	:warning:Warning	View (azure-python)	Details

docs-ref-services/latest/keyvault-secrets-readme.md

• Line 7, Column 13: [Warning: ms-service-subservice-invalid - See documentation] Invalid value for 'ms.service': 'keyvault'.
• Line 2, Column 1: [Suggestion: description-missing - See documentation] Missing required attribute: 'description'.
• Line 28, Column 3: [Suggestion: docs-link-absolute - See documentation] Absolute link 'https://docs.microsoft.com/azure/key-vault/general/overview' will be broken in isolated environments. Replace with a relative link.
• Line 49, Column 15: [Suggestion: docs-link-absolute - See documentation] Absolute link 'https://docs.microsoft.com/azure/key-vault/general/overview' will be broken in isolated environments. Replace with a relative link.
• Line 49, Column 137: [Suggestion: docs-link-absolute - See documentation] Absolute link 'https://docs.microsoft.com/azure/key-vault/general/quick-create-cli' will be broken in isolated environments. Replace with a relative link.
• Line 52, Column 373: [Suggestion: docs-link-absolute - See documentation] Absolute link 'https://docs.microsoft.com/azure/active-directory/managed-identities-azure-resources/overview' will be broken in isolated environments. Replace with a relative link.
• Line 77, Column 1: [Suggestion: docs-link-absolute - See documentation] Absolute link 'https://docs.microsoft.com/azure/key-vault/general/about-keys-secrets-certificates' will be broken in isolated environments. Replace with a relative link.
• Line 160, Column 28: [Suggestion: docs-link-absolute - See documentation] Absolute link 'https://docs.microsoft.com/azure/key-vault/general/soft-delete-overview' will be broken in isolated environments. Replace with a relative link.
• Line 161, Column 24: [Suggestion: docs-link-absolute - See documentation] Absolute link 'https://docs.microsoft.com/azure/key-vault/general/soft-delete-overview' will be broken in isolated environments. Replace with a relative link.

For more details, please refer to the build report.

Note: Your PR may contain errors or warnings or suggestions unrelated to the files you changed. This happens when external dependencies like GitHub alias, Microsoft alias, cross repo links are updated. Please use these instructions to resolve them.

For any questions, please:

• Try searching the learn.microsoft.com contributor guides
• Post your question in the Learn support channel

[learn-build-service-prod[bot]]

Learn Build status updates of commit 88c5388:

:warning: Validation status: warnings

File	Status	Preview URL	Details
docs-ref-services/latest/keyvault-secrets-readme.md	:warning:Warning	View (azure-python)	Details
metadata/latest/azure-keyvault-secrets.json	:white_check_mark:Succeeded

docs-ref-services/latest/keyvault-secrets-readme.md

• Line 7, Column 13: [Warning: ms-service-subservice-invalid - See documentation] Invalid value for 'ms.service': 'keyvault'.
• Line 2, Column 1: [Suggestion: description-missing - See documentation] Missing required attribute: 'description'.
• Line 28, Column 3: [Suggestion: docs-link-absolute - See documentation] Absolute link 'https://docs.microsoft.com/azure/key-vault/general/overview' will be broken in isolated environments. Replace with a relative link.
• Line 49, Column 15: [Suggestion: docs-link-absolute - See documentation] Absolute link 'https://docs.microsoft.com/azure/key-vault/general/overview' will be broken in isolated environments. Replace with a relative link.
• Line 49, Column 137: [Suggestion: docs-link-absolute - See documentation] Absolute link 'https://docs.microsoft.com/azure/key-vault/general/quick-create-cli' will be broken in isolated environments. Replace with a relative link.
• Line 52, Column 373: [Suggestion: docs-link-absolute - See documentation] Absolute link 'https://docs.microsoft.com/azure/active-directory/managed-identities-azure-resources/overview' will be broken in isolated environments. Replace with a relative link.
• Line 77, Column 1: [Suggestion: docs-link-absolute - See documentation] Absolute link 'https://docs.microsoft.com/azure/key-vault/general/about-keys-secrets-certificates' will be broken in isolated environments. Replace with a relative link.
• Line 160, Column 28: [Suggestion: docs-link-absolute - See documentation] Absolute link 'https://docs.microsoft.com/azure/key-vault/general/soft-delete-overview' will be broken in isolated environments. Replace with a relative link.
• Line 161, Column 24: [Suggestion: docs-link-absolute - See documentation] Absolute link 'https://docs.microsoft.com/azure/key-vault/general/soft-delete-overview' will be broken in isolated environments. Replace with a relative link.

For more details, please refer to the build report.

Note: Your PR may contain errors or warnings or suggestions unrelated to the files you changed. This happens when external dependencies like GitHub alias, Microsoft alias, cross repo links are updated. Please use these instructions to resolve them.

For any questions, please:

• Try searching the learn.microsoft.com contributor guides
• Post your question in the Learn support channel