Fix CI.yml

Author: fingolfin

.github/workflows/CI.yml

@@ -8,7 +8,7 @@ on:
 jobs:
   test:
     name: Julia ${{ matrix.version }} - ${{ github.event_name }}
-    runs-on: ${{ matrix.os }}
+    runs-on: ubuntu-latest
     strategy:
       fail-fast: false
       matrix:
@@ -21,7 +21,6 @@ jobs:
       - uses: julia-actions/setup-julia@v1
         with:
           version: ${{ matrix.version }}
-          arch: ${{ matrix.arch }}
       - uses: julia-actions/cache@v1
       - uses: julia-actions/julia-buildpkg@v1
       - uses: julia-actions/julia-runtest@v1