Test on the latest stable release

This makes it easier to understand if a failure is due to nightly being buggy

Author: jishnub

.github/workflows/CI.yml

@@ -22,6 +22,7 @@ jobs:
           - 'mkl'
         version:
           - '1.6'
+          - '1'
           - 'nightly'
         os:
           - ubuntu-latest