ci: set base branch for docs update PR (#155)

Author: matifali

.github/workflows/update-readme.yaml

@@ -33,6 +33,7 @@ jobs:
           title: 'chore: bump version to ${{ env.TAG }} in README.md files'
           body: 'This is an auto-generated PR to update README.md files of all modules with the new tag ${{ env.TAG }}'
           branch: 'update-readme-branch'
+          base: 'main'
         env:
           TAG: ${{ steps.get-latest-tag.outputs.TAG }}