CI: change '~1.8.0-0' to '1.8' (#723)

Author: DilumAluthge

.github/workflows/test.yml

@@ -21,7 +21,7 @@ jobs:
         julia-version:
           - '1.6'
           - '1.7'
-          - '~1.8.0-0'
+          - '1.8'
           - 'nightly'
         julia-arch:
           - 'x64'