[Weblate] diff-match-patch source is missing
the Python module `diff-match-patch` was installed via pip but with source. The upstream repo diff-match-patch-python doesn't know about the version `20121119` only about `20181111`.
There are other module sources on PiPy:https://pypi.org/project/diff-match-patch-cython/ with the version `20121119` pointing https://github.com/google/diff-match-patch, that has no tags nothing.
Currently the current Weblate 3.5 depends on ` 20121119`, but 3.7 depdends on `20181111`. So we can fix this issue, when we update Weblate to 3.7 and update diff-match-patch too.