updated the .github .yml files to fix dependabot issues

Author: mlampros

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

@@ -30,7 +30,7 @@ jobs:
       R_KEEP_PKG_SOURCE: yes
 
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v5
 
       - uses: r-lib/actions/setup-pandoc@v2
 

.github/workflows/pkgdown.yaml

@@ -23,7 +23,7 @@ jobs:
     permissions:
       contents: write
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v5
 
       - uses: r-lib/actions/setup-pandoc@v2