ci: stop building PDF and singlehtml on PR

We don't need to build PDF and singlehtml versions on every pull
requests, only on merge to master. So this patch removes this steps from
GitHub workflow file.

Author: lastoCHka42

.github/workflows/deploy-branch.yml

@@ -74,14 +74,6 @@ jobs:
         id: make-json
       - run: make json-ru
         id: make-json-ru
-      - run: make pdf
-        id: make-pdf
-      - run: make pdf-ru
-        id: make-pdf-ru
-      - run: make singlehtml
-        id: make-singlehtml
-      - run: make singlehtml-ru
-        id: make-singlehtml-ru
 
       - run: bash upload_output.sh
         id: upload-output