cicd: Simplify R CMD Check actions workflow 🤖

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

@@ -12,19 +12,12 @@ permissions: read-all
 
 jobs:
   R-CMD-check:
-    runs-on: ${{ matrix.config.os }}
-
-    name: ${{ matrix.config.os }} (${{ matrix.config.r }})
+    runs-on: ubuntu-latest
 
     strategy:
       fail-fast: false
       matrix:
-        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'}
+        R: [ 'release' ]
 
     env:
       GITHUB_PAT: ${{ secrets.GITHUB_TOKEN }}
@@ -37,8 +30,7 @@ jobs:
 
       - uses: r-lib/actions/setup-r@v2
         with:
-          r-version: ${{ matrix.config.r }}
-          http-user-agent: ${{ matrix.config.http-user-agent }}
+          r-version: ${{ matrix.R }}
           use-public-rspm: true
 
       - uses: r-lib/actions/setup-r-dependencies@v2
@@ -48,5 +40,6 @@ jobs:
 
       - uses: r-lib/actions/check-r-package@v2
         with:
+          error-on: '"error"'
           upload-snapshots: true
           build_args: 'c("--no-manual","--compact-vignettes=gs+qpdf")'