Ensure main is used on push.

When inputs are not mandatory in GitHub Actions, the default value is only used if the calling action does not specify the input. Otherwise, the input is defined with a falsey value.

Currently, the i18n Update Action is always passing the value if `inputs.base_branch`. But when the workflow runs on `push` events, this results in an the called workflow setting `base_branch` to an empty value.

Author: desrosj

.github/workflows/i18n-update.yml

@@ -19,6 +19,6 @@ jobs:
   call-i18n-update:
     uses: newfold-labs/workflows/.github/workflows/i18n-update.yml@main
     with:
-      base_branch: ${{ inputs.base_branch }}
+      base_branch: ${{ inputs.base_branch || 'main' }}
     secrets:
       NEWFOLD_ACCESS_TOKEN: ${{ secrets.NEWFOLD_ACCESS_TOKEN }}