Ensure it's always run, but only pushed on master

.github/workflows/build_docs.yml

@@ -1,8 +1,5 @@
 name: build docs
-on:
-  push:
-    branches:
-      - master
+on: push
 
 jobs:
   build_docs:
@@ -36,8 +33,12 @@ jobs:
             | grep "^slug:" | awk -F':' '{gsub(/^ +/, "", $2); print $2}' | sort | uniq -c \
             | awk '{if ($1 > 1) { print "duplicate slug for: " $2; exit 1}}'
 
+      - name: Print the lines of the generated docs
+        run: wc -l ooni-docs/src/content/docs/backend/*
+
       - name: Commit changes
-        id: commit
+        # Only push the docs update when we are in master
+        if: github.ref == 'refs/heads/master'
         run: |
           cd ooni-docs
           git config --global user.email "[email protected]"