diff --git a/.github/workflows/upgrade-python-requirements.yml b/.github/workflows/upgrade-python-requirements.yml
index 804c5253..17bb6a16 100644
--- a/.github/workflows/upgrade-python-requirements.yml
+++ b/.github/workflows/upgrade-python-requirements.yml
@@ -8,7 +8,7 @@ on:
        branch:
          description: 'Target branch to create requirements PR against'
          required: true
-         default: $default-branch
+         default: 'master'
 jobs:
    call-upgrade-python-requirements-workflow:
     with: