update r-cmd-check

Author: sbidari

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

@@ -1,11 +1,15 @@
 # Workflow derived from https://github.com/r-lib/actions/tree/v2/examples
 # Need help debugging build failures? Start at https://github.com/r-lib/actions#where-to-find-help
+name: R-CMD-check.yaml
+
 on:
-  push:
-    branches: [main, master]
   pull_request:
+  push:
+    branches: [main]
 
-name: R-CMD-check.yaml
+concurrency:
+  group: ${{ github.workflow }}-${{ github.head_ref || github.ref }}
+  cancel-in-progress: true
 
 permissions: read-all
 
@@ -21,9 +25,7 @@ jobs:
         config:
           - {os: macos-latest,   r: 'release'}
           - {os: windows-latest, r: 'release'}
-          - {os: ubuntu-latest,   r: 'devel', http-user-agent: 'release'}
-          - {os: ubuntu-latest,   r: 'release'}
-          - {os: ubuntu-latest,   r: 'oldrel-1'}
+          - {os: ubuntu-latest,  r: 'release'}
 
     env:
       GITHUB_PAT: ${{ secrets.GITHUB_TOKEN }}