GitLab

Recent python-for-android changes require to:
- use the NDK r19
- update the binary output path
- update buildozer to recent master fixes

Also installs `buildozer` under Python3 via `pip3` as some of the build
steps now requires Python3.
Note that python2.7 is still a required dependency from buildozer, refs:
https://github.com/kivy/buildozer/blob/586152c/buildozer/__init__.py#L582

Uses the `HTTP` check mode to parse the `version.py` from the git repo.

This is needed after fdroidserver!637 was merged.
The error was:
```
CRITICAL: Android NDK version 'r17b' could not be found!
```
See:
https://f-droid.org/wiki/page/com.github.andremiras.etheroll/lastbuild_202117

Also bumps buildozer version so it doesn't fail silently, refs:
https://github.com/kivy/buildozer/issues/674

Fix lint error

Cross platform Etheroll app built with Python and Kivy.
Uses an Ethereum smart contract to place bets on the blockchain.

Note the introduction of `srclibs/buildozer.txt` to use the
non-mainstream `buildozer` wrapper.

The build relies on buildozer master (post 0.39 release) which fixes
issues with unsigned releases.
Cython is pinned since this is the official tested version with
buildozer.
Both SDK and NDK path are set to use fdroid ones.
The auto accept license is disabled since fdroid sdkmanager doesn't
support the --licenses argument.