pre-commit-detect-outdated.yml: Fix main branch target

.. to match status quo reality

Author: hartwork

.github/workflows/pre-commit-detect-outdated.yml

@@ -45,7 +45,7 @@ jobs:
         uses: peter-evans/create-pull-request@6d6857d36972b65feb161a90e484f2984215f83e  # v6.0.5
         with:
           author: 'pre-commit <[email protected]>'
-          base: main
+          base: master
           body: |-
             For your consideration.