GH Actions/update website: minor tweak

The test PR created a new label `"Type: documentation"` due to the quotes used in the script. This removes the quotes, though it remains to be seen if that works correctly as it _may_ confuse Yaml due to the `:` colon in the label.

If this doesn't work, the issue should probably be reported upstream to the `peter-evans/create-pull-request` project.

.github/workflows/update-website.yml

@@ -159,7 +159,7 @@ jobs:
 
             This PR is auto-generated by [create-pull-request](https://github.com/peter-evans/create-pull-request).
           labels: |
-            "Type: documentation"
+            Type: documentation
           reviewer: |
             jrfnl
             schlessera