fix: relax dependencies

[ceholden]

Description

This PR relaxes the Click dependency so this can be installed against a more modern set of dependencies in our atmospheric correction container.

I updated the tests to run on a newer version of Python to modernize in general, but specifically because the CI failed to install Python 3.6 since it's deprecated.

The removal of pin on numpy was pretty trivial. Bumping mypy caused so many linting issues, many related to the poor typing with numpy.ma 😭

Of note is the re-pin for pystac (similar to NASA-IMPACT/hls-cmr_stac#11),

1. pystac[validation]==1.0.0rc2 doesn't work against modern versions of jsonschema. Instead of pinning jsonschema I opted to bump pystac ()
2. pystac==1.12.0 introduces a breaking change in the proj extension (proj:epsg -> proj:code) that was caught in our tests 🙏.
3. pystac<=1.12.0 is still on STAC version 1.0.0, but I'm also going to specify in our container that we should be using stac==1.0.0 by defining the PYSTAC_STAC_VERSION_OVERRIDE envvar. I also set this in the STAC generation code.
4. I had to update test values for two STAC extensions to bump minor versions since PySTAC bumps will force bumps to STAC extensions.