Fix OpenAPI parameters containing other parameters (spec-first#1523)

* Fix OpenAPI parameters containing other parameters

OpenAPI parameters can be unspecified and sometimes contain other
parameters. The current behavior is to assume it's a bracket parameter
and nest the containing parameter within the contained parameter, which
breaks the schema as the original parameter now seems to contain a
nested object.

We can avert this by checking for the presence of a '[' in the
parameter.

* Trigger Github workflow

Co-authored-by: Ricardo Piro-Rael <rpiro-rael@ironox.com>

Bugfix/async security check (spec-first#1512)

* Add failing tests

* Use for else construct

Drop pkg_resources (spec-first#1499)

* Use pkgutil instead of pkg_resources

* Use importlib.metadata and packaging for getting and parsing version number

Remove sanitization of body properties (spec-first#1469)

Use NullableEnumValidator for enum (spec-first#1464)

Add Python 3.9 to supported versions in setup.py (spec-first#1459)

Only push to TestPyPi on tag trigger (spec-first#1457)

improved error 415 (spec-first#1185)

* improved error 415

* test added

* Fix tests for updated 415 error response

Co-authored-by: unknown <parthsujalshah@gmail.com.com>
Co-authored-by: Ruwan <ruwanlambrichts@gmail.com>

Allow "Required: False" on Response headers - Fix spec-first#1261 (sp…

…ec-first#1293)

* Add failing test for optional header

* Required: False headers don't give error if missing

* Use dict.get

* Required keys are when they are not present, or present with "True"

* Update connexion/decorators/response.py

Co-authored-by: Ruwann <ruwan.lambrichts@ml6.eu>

* Update tests for required and optional headers

Swagger2 response headers are optional, and have no 'required'
attribute. OpenAPI3 response headers are optional by default,
but can be specified to be required by setting 'required: true'.

* Make headers required for tests that rely on it

Co-authored-by: Ruwann <ruwan.lambrichts@ml6.eu>

Add readthedocs config with docs requirements (spec-first#1391)