Exercise the test on all OSes

Author: jennybc

.github/workflows/R-CMD-check.yaml

@@ -58,7 +58,7 @@ jobs:
           needs: check
 
       - name: git config
-        if: matrix.config.os == 'ubuntu-latest' && matrix.config.r == 'release'
+        if: matrix.config.r == 'release'
         run: |
           git config --global user.name "$GITHUB_ACTOR"
           git config --global user.email "[email protected]"