Update pkgdown.yaml

Update permissions to write to repo

.github/workflows/pkgdown.yaml

@@ -5,6 +5,10 @@ on:
 
 name: pkgdown
 
+permissions:
+  contents: write
+  actions: read
+
 jobs:
   pkgdown:
     runs-on: ubuntu-20.04
@@ -35,4 +39,4 @@ jobs:
         run: |
           git config --local user.name "$GITHUB_ACTOR"
           git config --local user.email "$GITHUB_ACTOR@users.noreply.github.com"
-          Rscript -e 'pkgdown::deploy_to_branch(new_process = FALSE, branch = "gh-pages", github_pages = TRUE)'
+          Rscript -e 'pkgdown::deploy_to_branch(new_process = FALSE, branch = "gh-pages", github_pages = TRUE)'