Merge pull request #1025 from tahoe-lafs/3616.py36-on-github-actions

Run coverage tests with Python 3.6 on GitHub Actions

Fixes ticket:3616

.github/workflows/ci.yml

@@ -20,8 +20,19 @@ jobs:
         os:
           - macos-latest
           - windows-latest
+          - ubuntu-latest
         python-version:
           - 2.7
+          - 3.6
+        exclude:
+          # Do not run coverage tests with Python 3.6 on Windows for
+          # now.  They will fail.  Dealing with them separately would
+          # be simpler.
+          #
+          # XXX: https://tahoe-lafs.org/trac/tahoe-lafs/ticket/3669
+          # should track the effort to add Windows to the test matrix.
+          - python-version: 3.6
+            os: windows-latest
 
     steps: