remove nightly from CI

Author: itsdfish

.github/workflows/CI.yml

@@ -16,7 +16,6 @@ jobs:
       matrix:
         version:
           - '1.11' # Replace this with the minimum Julia version that your package supports. E.g. if your package requires Julia 1.5 or higher, change this to '1.5'.
-          - 'nightly'
         os:
           - ubuntu-latest
         arch: