fix GA

Author: davidgohel

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

@@ -19,7 +19,7 @@ jobs:
       matrix:
         config:
           - {os: macOS-latest, r: 'release'}
-          - {os: ubuntu-20.04, r: 'release'}
+          - {os: ubuntu-latest, r: 'release'}
           - {os: windows-latest, r: 'release'}
 
     env: