Update dependencies and do not install reflink on Windows for tests

[snejus]

See my comment under #5406 for context

The build on win32 is failing to install reflink because it's only supported until Python 3.7.

I will address this in a separate PR and rebase this one accordingly once the fix is merged.

Note: this issue popped up now because I added a new requests-mock dependency which invalidated cached dependencies.

[github-actions]

Thank you for the PR! The changelog has not been updated, so here is a friendly reminder to check if you need to add an entry.

[bal-e]

LGTM, I think?