(AB#265868) Update for June releases (7.4.3, 7.2.21)

[michaeltlombardi]

PR Summary

This change:

• Updates the install docs and release notes for the June PowerShell releases (v7.4.3 and v7.2.21).
• Fixes AB#265868

PR Checklist

• [x] Descriptive Title: This PR's title is a synopsis of the changes it proposes.
• [x] Summary: This PR's summary describes the scope and intent of the change.
• [x] Contributor's Guide: I have read the contributors guide.
• [x] Style: This PR adheres to the style guide.

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

Learn Build status updates of commit f1851b6:

:white_check_mark: Validation status: passed

File	Status	Preview URL	Details
reference/docs-conceptual/install/community-support.md	:white_check_mark:Succeeded	View (>=powershell-5.1)
reference/docs-conceptual/install/install-alpine.md	:white_check_mark:Succeeded	View (>=powershell-5.1)
reference/docs-conceptual/install/install-debian.md	:white_check_mark:Succeeded	View (>=powershell-5.1)
reference/docs-conceptual/install/install-rhel.md	:white_check_mark:Succeeded	View (>=powershell-5.1)
reference/docs-conceptual/install/install-ubuntu.md	:white_check_mark:Succeeded	View (>=powershell-5.1)
reference/docs-conceptual/install/Installing-PowerShell-on-macOS.md	:white_check_mark:Succeeded	View (>=powershell-5.1)
reference/docs-conceptual/install/Installing-PowerShell-on-Windows.md	:white_check_mark:Succeeded	View (>=powershell-5.1)
reference/docs-conceptual/install/microsoft-update-faq.yml	:white_check_mark:Succeeded	View (>=powershell-5.1)
reference/docs-conceptual/whats-new/What-s-New-in-PowerShell-74.md	:white_check_mark:Succeeded	View (>=powershell-5.1)

For more details, please refer to the build report.

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 af8088f:

:white_check_mark: Validation status: passed

File	Status	Preview URL	Details
reference/docs-conceptual/install/community-support.md	:white_check_mark:Succeeded	View (>=powershell-5.1)
reference/docs-conceptual/install/install-alpine.md	:white_check_mark:Succeeded	View (>=powershell-5.1)
reference/docs-conceptual/install/install-debian.md	:white_check_mark:Succeeded	View (>=powershell-5.1)
reference/docs-conceptual/install/install-rhel.md	:white_check_mark:Succeeded	View (>=powershell-5.1)
reference/docs-conceptual/install/install-ubuntu.md	:white_check_mark:Succeeded	View (>=powershell-5.1)
reference/docs-conceptual/install/Installing-PowerShell-on-macOS.md	:white_check_mark:Succeeded	View (>=powershell-5.1)
reference/docs-conceptual/install/Installing-PowerShell-on-Windows.md	:white_check_mark:Succeeded	View (>=powershell-5.1)
reference/docs-conceptual/install/microsoft-update-faq.yml	:white_check_mark:Succeeded	View (>=powershell-5.1)
reference/docs-conceptual/whats-new/What-s-New-in-PowerShell-74.md	:white_check_mark:Succeeded	View (>=powershell-5.1)

For more details, please refer to the build report.

For any questions, please:

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