Fix Matrix Issue with Pinned Versions

[gagelarsen]

Description

This merge request addresses an issue where running the install script didn't pin to a specific version of python or Django. It was only setting the lower bounds. We want to pin it when we set a version.

Changes Made to Code:

• Update the install script to set version to be == rather than >=
• Fix python version flag to be -p rather than -v to match usage notes
• Update the docker file to sed the python version correctly

Related

• None

Additional Notes

• This was found when trying to update the tethysext-atcore dockers.

Quality Checks

• [x] New code is 100% tested
• [x] Code has been formated
• [x] Code has been linted
• [x] Docstrings for new methods have been added

[coveralls]

coverage: 100.0%. remained the same when pulling f42d6b566726ce4cac21c980c9398c7b00301077 on fix_install_script into 569e8dab4761ea4c16c45dbdeb889dd85898a1f2 on main.