Require build-docs label only when making a pull request to upstream/…

…main

.github/workflows/build-docs.yml

@@ -12,7 +12,7 @@ defaults:
     shell: bash -le {0}
 jobs:
   build-sphinx-html:
-    if: (((github.repository == 'tardis-sn/stardis') && (${{ github.head_ref || github.ref_name}} == 'main')) || (github.repository_owner != 'tardis-sn')) && contains(github.event.pull_request.labels.*.name, 'build-docs')
+    if: ((github.repository == 'tardis-sn/stardis') && (${{ github.head_ref || github.ref_name}} == 'main') && contains(github.event.pull_request.labels.*.name, 'build-docs')) || (github.repository_owner != 'tardis-sn') 
     # The above line makes this action run if it is either not on the upstream/main or the main branch of upstream/main.
     # If there is a better way to implement this, I'd like someone to please share.
     # The context to get the branch name is from https://stackoverflow.com/a/71158878