Show a deprecation notice that points to lstk aws

[anisaoshafi]

awslocal now prints a deprecation notice to stderr on every run. It points users to lstk aws and the migration guide. It reuses the notice structure from the localstack CLI (DEVX-1126).

============================================================================
  WARNING: 'awslocal' is deprecated. Use 'lstk aws' instead.
============================================================================

  'awslocal' no longer receives updates.

  Get started with 'lstk', the new LocalStack CLI:
  https://docs.localstack.cloud/aws/developer-tools/running-localstack/lstk/

  Switch your scripts and CI workflows to 'lstk aws':
  https://docs.localstack.cloud/aws/developer-tools/running-localstack/lstk/migration/#infrastructure-as-code

============================================================================

Continuing with 'awslocal'...

• Stdout stays clean, so piped output still works.
• DISABLE_DEPRECATION_NOTICE=1 hides the notice.
• Adds the same note to the README and bumps the version to 0.23.0.
• CI fix: pins boto3 in the awscli==1.41.0 job. New boto3 releases need a newer botocore than that awscli allows, so the job failed on import.

Resolves DEVX-1166

[github-actions]

Smoke Tests

 6 files  ± 0  18 suites  +6   3m 30s ⏱️ +5s
 7 tests + 3   7 ✅ + 3  0 💤 ±0  0 ❌ ±0 
42 runs  +18  42 ✅ +18  0 💤 ±0  0 ❌ ±0 

Results for commit d93a56a. ± Comparison against base commit 691ec32.

♻️ This comment has been updated with latest results.