Check for PYGEOAPI_OPENAPI Env Var Before Generating openapi.yml in Entrypoint

[yharby]

Overview

This PR enhances the entrypoint.sh script to check for the existence of the PYGEOAPI_OPENAPI environment variable before generating openapi.yml when the geopython/pygeoapi Docker container starts. This update allows users to mount a custom openapi.yml file without it being overwritten, offering greater flexibility for customized configurations.

Related Issue / discussion

Addresses issue #1849.

Additional information

• The update maintains the original logic and flow of the entrypoint.sh script while adding a simple check for the PYGEOAPI_OPENAPI variable, ensuring user-mounted configurations are preserved.

Dependency policy (RFC2)

• I have ensured that this PR meets RFC2 requirements

Updates to public demo

• I have ensured that breaking changes to the pygeoapi master demo server have been addressed
  • https://github.com/geopython/demo.pygeoapi.io/blob/master/services/pygeoapi_master/local.config.yml

Contributions and licensing

(as per Contributions and Licensing Guidelines)

• I'd like to contribute this feature to pygeoapi. I confirm that my contributions to pygeoapi will be compatible with the pygeoapi license guidelines at the time of contribution.
• I have already previously agreed to the pygeoapi Contributions and Licensing Guidelines.