make sure to test on 1.5 and 1.6

Author: Jutho

.github/workflows/ci.yml

@@ -11,7 +11,8 @@ jobs:
       matrix:
         version:
           - '1.4'
-          - '1' # automatically expands to the latest stable 1.x release of Julia
+          - '1.5'
+          - '1.6-nightly'
         os:
           - ubuntu-latest
           - macOS-latest