Update r.yml

Author: soodoku

.github/workflows/r.yml

@@ -19,7 +19,7 @@ jobs:
     runs-on: macos-latest
     strategy:
       matrix:
-        r-version: ['3.6.3', '4.1.1']
+        r-version: ['4.2']
 
     steps:
       - uses: actions/checkout@v2