Disable fail-fast in Github Actions configuration

By default, Github Actions has the fail-fast option enabled, which means
that the first job to fail in a matrix causes the whole matrix to be
immediately canceled. This makes it impossible to identify when a bug
causing a job failure is specific to certain versions of Python. In this
commit I'm setting the option to false so that each job will run to
completion even if one fails.

Author: diazona

.github/workflows/tests.yml

@@ -12,6 +12,7 @@ jobs:
         # Not all Python versions are avalaible for linux AND x64
         # https://raw.githubusercontent.com/actions/python-versions/main/versions-manifest.json
         python-version: [2.7, 3.5, 3.6, 3.7, 3.8, 3.9, '3.10']
+      fail-fast: false
 
     steps:
     - uses: actions/checkout@v1