Update awscrt requirement from <=0.20.11,>=0.19.18 to >=0.19.18,<=0.21.2

[dependabot[bot]]

Updates the requirements on awscrt to permit the latest version.

Release notes

Sourced from awscrt's releases.

Mark the network interface API experimental

What's Changed

• Mark the network interface API experimental by @​waahm7 in awslabs/aws-crt-python#580

Full Changelog: https://github.com/awslabs/aws-crt-python/compare/v0.21.1...v0.21.2

Commits

• 436d58c Mark the network interface API experimental (#580)
• 97b7189 Support machines with multiple NICs (#576)
• 717e4d2 fix FreeBSD CI to install default python packages (#579)
• 1424d91 S3Client breaking change: DEFAULT requests must pass operation_name (#574)
• 00a410f Fix editable build on Macs with XCode >= 15 (#575)
• 1d5103e Always use virtual environments in CI, because PEP 668 (#573)
• a486d70 clang-format 18 (#571)
• e88cce2 latest submodules (#570)
• c9c84bc Address issues with latest AWS-LC and OpenBSD (#569)
• 4a4fd22 fix docs.yml (#568)
• Additional commits viewable in compare view

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[nateprewitt]

Superseded by #8844.

[dependabot[bot]]

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