Added devtools as dep in GHA

Author: VisruthSK

.github/workflows/pkgdown.yaml

@@ -33,7 +33,7 @@ jobs:
 
       - uses: r-lib/actions/setup-r-dependencies@v2
         with:
-          extra-packages: any::pkgdown, local::.
+          extra-packages: any::pkgdown, any::devtools, local::.
           needs: website
 
       - name: Build site