Allowing four parallel test jobs

Author: chr1st1ank

.github/workflows/code_quality.yml

@@ -35,7 +35,7 @@ jobs:
     runs-on: ubuntu-latest
 
     strategy:
-      max-parallel: 3
+      max-parallel: 4
       matrix:
         python-version: ["3.7", "3.8", "3.9", "3.10.0-alpha.6"]