Don't fail fast when running tests

This avoids the need to play whack-a-mole with CI failures, like I had
to deal with on #518. Everything should be laid out on the table once.
This saves everyone time.

Author: djmattyg007

.github/workflows/test.yml

@@ -8,6 +8,7 @@ jobs:
   test:
     runs-on: ubuntu-latest
     strategy:
+      fail-fast: false
       matrix:
         python-version:
           - 2.7