Make id generation customizable (#203)

Branca/folium uses random numbers to generate ids. This has some
disadvantages. E.g. in the streamlit-folium plugin they have to
replace the random ids with predictable ids for comparison between
streamlit runs.

Also, in the folium tests, we have to normalize the variable names
to compare between expected and actual results. This change in Branca
makes it possible to override or customize id generation. This allows
client libraries to experiment with new id generation schemes.

Add py.typed file (#183)

[pre-commit.ci] pre-commit autoupdate

updates:
- [github.com/asottile/pyupgrade: v3.15.2 → v3.16.0](asottile/pyupgrade@v3.15.2...v3.16.0)

[pre-commit.ci] pre-commit autoupdate

updates:
- [github.com/psf/black: 24.3.0 → 24.4.0](psf/black@24.3.0...24.4.0)

Add jinja2 version constraint

Branca does not work with some older versions of Jinja2, resulting in an `ImportError: cannot import name 'soft_unicode' from 'markupsafe'` (for e.g. `import branca.colormap as colormap`). To address this issue, we have added a version constraint for `Jinja2>=3`.

[pre-commit.ci] pre-commit autoupdate

updates:
- [github.com/keewis/blackdoc: v0.3.8 → v0.3.9](keewis/blackdoc@v0.3.8...v0.3.9)

Merge pull request #122 from ocefpaf/drop_py36

drop py36

Update CHANGES.txt for 0.5.0 release

Update CHANGES.txt

Update CHANGES.txt