handle youtube-dl's ChangeLog file correctly (partially tested)

.github/workflows/build.yml

@@ -44,7 +44,7 @@ jobs:
     - name: Get Changelog
       id: get_changelog
       run: |
-        changelog=$(cat ChangeLog | grep -oPz '(?s)(?<=### ${{ steps.bump_version.outputs.ytdl_version }}\n{2}).+?(?=\n{2,3}###)') || true
+        changelog=$(cat ChangeLog | grep -oPz '(?s)(?<=version ${{ steps.bump_version.outputs.ytdl_version }}\n{2}).+?(?=\n{2,3}version)') || true
         echo "changelog<<EOF" >> $GITHUB_ENV
         echo "$changelog" >> $GITHUB_ENV
         echo "EOF" >> $GITHUB_ENV