Lifted pin on sqlalchemy in order to be able to use v2+

[ricardogsilva]

Overview

This PR lifts the pin on the sqlalchemy dependency, removing the requirement to use a version lower than v2.

Related Issue / discussion

• Allow using sqlalchemy > 2 #1661

Additional information

WRT RFC2, and as mentioned in my previous comment at the issue:

#1661 (comment)

The current code base should be compatible with both sqlalchemy v1.4 (which is what is included in current ubuntu LTS repos) and with v2, which means we can continue to use v1.4 from the current ubuntu LTS repos when doing a 'bare metal' install and also means we can use the current version of sqlalchemy when installing via other methods, like pip.

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 https://github.com/geopython/pygeoapi/blob/master/CONTRIBUTING.md#contributions-and-licensing)

• I'd like to contribute [feature X|bugfix Y|docs|something else] 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

[ricardogsilva]

@tomkralidis CI error seems unrelated to the changes in the PR - seems like some trivy limit has been reached. I think it would likely go away if the job is re-run. I am not able to ask for a re-run of the failed CI JOB though