CREATE_PR doesnt seem to be working with `on:push`

[guergana]

Describe the bug: バグの概要

The action creates a commit properly but given the flag CREATE_PR it doesn't create a PR with the ToC.
This was tested when pushing to a specific folder. I don't know if the CREATE_PR flag is working when no folder is specified.

To Reproduce: 再現手順

Steps to reproduce the behavior:

1. Create a workflow that uses the CREATE_PR flag:

 name: Update Table of Contents (ToC)

on: 
  push:
    paths: 
      - docs/**

jobs:
  generateTOC:
    name: TOC Generator
    runs-on: ubuntu-latest
    steps:
      - uses: technote-space/toc-generator@v4
        with:
          CREATE_PR: true
          TARGET_PATHS: ./docs/*.md

2. Push some changes to specified folder. The workflow will run and create a commit at the end of the PR that created the changes in the folder.
3. Check github, the create PR prompt is not triggered.

Expected behavior: 期待する動作

A PR is opened with on:push event.

The flag works with on:pull_request event.

Additional context: 補足

This was tested on the following PR: wmde/wikidata-mismatch-finder#720

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