Trying to fix GitHub Action errors on previous versions of Ubuntu

Author: stephaniereinders

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

@@ -30,6 +30,11 @@ jobs:
     steps:
       - uses: actions/checkout@v4
 
+      - name: Install system dependencies
+        run: |
+          sudo apt-get update
+          sudo apt-get install -y libgsl-dev
+
       - uses: r-lib/actions/setup-pandoc@v2
 
       - uses: r-lib/actions/setup-r@v2
@@ -46,4 +51,4 @@ jobs:
       - uses: r-lib/actions/check-r-package@v2
         with:
           upload-snapshots: true
-          build_args: 'c("--no-manual","--compact-vignettes=gs+qpdf")'
+          build_args: 'c("--no-manual","--compact-vignettes=gs+qpdf")'