fix (#1100): FastAPI 0.106 compatibility

[Lancetnik]

Description

• FastAPI "0.106+" compatibility
• NATS max_workers option

  @nats_broker(..., max_workers=10)
  async def handler(...):
      """
      Consumes messages from subject concurently in the pool
      (up to 10 messages in the same time)
      """

Fixes #1100, close #1099

Type of change

Please delete options that are not relevant.

• Documentation (typos, code examples, or any documentation updates)
• Bug fix (a non-breaking change that resolves an issue)
• New feature (a non-breaking change that adds functionality)
• Breaking change (a fix or feature that would disrupt existing functionality)
• This change requires a documentation update

Checklist

• My code adheres to the style guidelines of this project (scripts/lint.sh shows no errors)
• I have conducted a self-review of my own code
• I have made the necessary changes to the documentation
• My changes do not generate any new warnings
• I have added tests to validate the effectiveness of my fix or the functionality of my new feature
• Both new and existing unit tests pass successfully on my local environment by running scripts/test-cov.sh
• I have ensured that static analysis tests are passing by running scripts/static-anaylysis.sh
• I have included code examples to illustrate the modifications