Update workflow to fix an issue with MacOS

Author: giabaio

.github/workflows/check-standard.yaml

@@ -1,5 +1,4 @@
 # Workflow derived from https://github.com/r-lib/actions/tree/master/examples
-# Need help debugging build failures? Start at https://github.com/r-lib/actions#where-to-find-help
 
 on:
   push:
@@ -47,10 +46,14 @@ jobs:
           print(getOption("repos"))
         shell: Rscript {0}
 
+      # macOS-only: remove lockfile to prevent pak crash
+      - name: Remove pak lockfile (macOS workaround)
+        if: matrix.config.os == 'macOS-latest'
+        run: rm -f .github/pkg.lock
+
       - uses: r-lib/actions/setup-r-dependencies@v2
         with:
           dependencies: '"all"'
-          cache: ${{ matrix.config.os != 'macOS-latest' }}
           extra-packages: |
             rcmdcheck
             rstan