Added GitHub Actions badge

[radarhere]

Adds GitHub Actions badge after #169 added GitHub Actions

See https://github.com/radarhere/pillow-wheels/blob/badge/README.rst as a preview.

[hugovk]

And let's put GHA first, that's the primary wheel builder.

Thanks!

[hugovk]

It's not caused by this PR, but any idea why the macOS jobs are failing? There's a bunch of Python 2 warnings in there too.

  Uninstalling virtualenv-20.2.2:
    Successfully uninstalled virtualenv-20.2.2
  DEPRECATION: Python 2.7 will reach the end of its life on January 1st, 2020. Please upgrade your Python as Python 2.7 won't be maintained after that date. A future version of pip will drop support for Python 2.7. More details about Python 2 support in pip, can be found at pip.pypa.io/en/latest/development/release-process/#python-2-support
  WARNING: The directory '/Users/runner/Library/Caches/pip/http' or its parent directory is not owned by the current user and the cache has been disabled. Please check the permissions and owner of that directory. If executing pip with sudo, you may want sudo's -H flag.
  Uninstalling pip-19.3.1:
    Successfully uninstalled pip-19.3.1
  dyld: Library not loaded: /usr/local/opt/zstd/lib/libzstd.1.dylib
    Referenced from: /usr/local/opt/curl/bin/curl
    Reason: image not found
  multibuild/osx_utils.sh: line 277:  1676 Abort trap: 6           curl $MACPYTHON_URL/$py_stripped/${py_inst} > $inst_path
  Error: Process completed with exit code 134.

[nulano]

@hugovk I'm looking into it right now. I see that the Python 2 warnings happened in successful runs as well (probably just need to change pip to python -m pip), but now curl is failing because it seems to depend on the brew zstd package which was causing conflicts with wheel building so it is removed at the start of the script.

[nulano]

I found a fix for the error (just need to remove curl from brew and use the system curl), but I'm a bit hesitant to open a PR. The Travis build in this repo takes around 1200 credits by my calculations which would make it the last arm build before the credits run out. Is it possible to disable Travis on PRs here to buy a bit more time before the credits run out?

[hugovk]

Good idea!

You can add [CI skip] to commit messages, which disables Travis (and AppVeyor). GHA ignores it. But I think that'd still trigger a Travis build on merge.

For now, I've flipped these left two toggles off:

https://travis-ci.com/github/python-pillow/pillow-wheels/builds

Let's remember to turn them back on for the release :)

I think I'll turn the other off too. Will comment on the main issue.

[nulano]

Oh right, I keep forgetting about [ci skip] because GHA doesn't support it. I added it to the commit message just to make sure Travis doesn't run and opened #173.