fix test groups

Author: ChrisRackauckas

.github/workflows/CI.yml

@@ -34,6 +34,8 @@ jobs:
             ${{ runner.os }}-
       - uses: julia-actions/julia-buildpkg@v1
       - uses: julia-actions/julia-runtest@v1
+        env:
+          GROUP: ${{ matrix.group }}
       - uses: julia-actions/julia-processcoverage@v1
       - uses: codecov/codecov-action@v1
         with: