chore: Run docs search indexing on master branch

The "docs" branch is no longer used, so the index was not getting
updated.

.github/workflows/docsearch.yml

@@ -3,7 +3,7 @@ name: Index docs to Typesense
 on:
   push:
     branches:
-      - docs
+      - master
 
 jobs:
   index_docs: