Downgrade macos version for R-CMD-check

Author: mathesong

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

@@ -27,7 +27,7 @@ jobs:
       fail-fast: false
       matrix:
         config:
-          - {os: macos-latest,   r: 'release'}
+          - {os: macos-13,   r: 'release'}
           - {os: windows-latest, r: 'release'}
           - {os: ubuntu-latest,   r: 'devel', http-user-agent: 'release'}
           - {os: ubuntu-latest,   r: 'release'}