Update CI.yml

Author: ChrisRackauckas

.github/workflows/CI.yml

@@ -14,11 +14,12 @@ jobs:
         group:
           - Core
           - Downstream
+        version:
+          - '1'
+          - '1.6'
     steps:
       - uses: actions/checkout@v2
       - uses: julia-actions/setup-julia@v1
-        with:
-          version: 1
       - uses: actions/cache@v1
         env:
           cache-name: cache-artifacts