fix ci issue

[takojunior]

Hi @skadio , this PR is to fix the failing CI checks. I see that CI checks failed because python 3.7 is no longer supported in runner image `macos-latest' (that is macos 14) for tests. So I think it could be ok to drop 3.7.

We can add 3.11 instead. Some tests failed in 3.12 though, due to common packages not found in the image. So 3.11 seems far enough for now.

Then I updated installation information in readme and docs, for being consistent to tests. Since these are docs changes, and no library code changes, I think we don't need to update release version or changelog.