* remove non-tested django versions from the list of tested versions in the readme
* add snippet on generating SECRET_KEYs
* add contributing readme
* [pre-commit.ci] auto fixes from pre-commit.com hooks
for more information, see https://pre-commit.ci
* add file filter for github actions lint-and-test workflow
* add path filters for the lint and test github actions workflow
* use path-ignore instead of path for file filters
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Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>
