Merge pull request #133 from jdb78/maintenance/pytorch-lightning-1.0.4

Forbid pytorch lightning 1.0.4 as it breaks the code

Author: jdb78

.github/workflows/test.yml

@@ -15,7 +15,7 @@ jobs:
     strategy:
       matrix:
         os: [ubuntu-18.04, macOS-10.15] # add windows-2019 when poetry allows installation with `-f` flag
-        python-version: [3.6, 3.7, 3.8, 3.9]
+        python-version: [3.6, 3.7, 3.8] # python 3.9 is not supported by all dependencies yet
 
     steps:
       - uses: actions/checkout@v2