disable fail-fast

Author: basnijholt

.github/workflows/tox.yml

@@ -8,6 +8,7 @@ jobs:
   build:
     runs-on: ${{ matrix.platform }}
     strategy:
+      fail-fast: false
       matrix:
         platform: [ubuntu-latest, macos-latest, windows-latest]
         python-version: [3.6, 3.7, 3.8, 3.9]