make CI successful if at least one configuration succeeds

Author: rfhb

.github/workflows/check-standard.yml

@@ -12,8 +12,9 @@ jobs:
 
     name: ${{ matrix.config.os }} (${{ matrix.config.r }})
 
+    continue-on-error: true
+
     strategy:
-      fail-fast: false
       matrix:
         config:
           - {os: macos-latest,   r: 'release'}