Update ci.yml

Author: ppalmes

.github/workflows/ci.yml

@@ -15,7 +15,7 @@ jobs:
       fail-fast: false
       matrix:
         version:
-          - '1.8'
+          - '1.6'
           - '1' # Leave this line unchanged. '1' will automatically expand to the latest stable 1.x release of Julia.
           - 'nightly'
         python: [3.9]