Add 3.11-dev to tested environments list (#661)

Author: asvetlov

.github/workflows/ci.yml

@@ -61,7 +61,7 @@ jobs:
     needs: lint
     strategy:
       matrix:
-        pyver: ['3.6', '3.7', '3.8', '3.9', '3.10']
+        pyver: ['3.6', '3.7', '3.8', '3.9', '3.10', '3.11-dev']
         no-extensions: ['', 'Y']
         os: [ubuntu, macos, windows]
         exclude: