[Docs] Commit and push only subdir to another branch (GitHub/CodeBerg Pages)

I have currently a _workflow_ with an **build** step and a **deploy** step, that works as expected:

```yml
when:
- event: push
branch: main

steps:
build:
image: node:slim
commands:
- corepack enable
- pnpm install --frozen-lockfile
- pnpm run build

deploy:
image: alpine/git
secrets:
- git_token
environment:
- BUILD_DIR=dist
- TARGET_BRANCH=pages
commands:
# Git configuration
- git config --global user.name "$CI_COMMIT_AUTHOR"
- git config --global user.email "$CI_COMMIT_AUTHOR_EMAIL"
- git clone -b $TARGET_BRANCH https://$GIT_TOKEN@codeberg.org/${CI_REPO}.git $TARGET_BRANCH
# Copy build
- cp -ar $BUILD_DIR/. $TARGET_BRANCH/
- cp .domains $CI_REPO_NAME || true # Ignore if it doesn't exist
# Commit & Push
- cd $TARGET_BRANCH
- git add .
- git diff-index --quiet HEAD || git commit -m "$CI_COMMIT_MESSAGE"
- git push
```

How can i achieve the _same_ as:
```yml
...

steps:
...

deploy:
image: alpine/git
secrets:
- git_token
environment:
- BUILD_DIR=dist
- TARGET_BRANCH=pages
commands:
# Git configuration
- git config --global user.name "$CI_COMMIT_AUTHOR"
- git config --global user.email "$CI_COMMIT_AUTHOR_EMAIL"
- git clone -b $TARGET_BRANCH https://$GIT_TOKEN@codeberg.org/${CI_REPO}.git $TARGET_BRANCH
# Copy build
- cp -ar $BUILD_DIR/. $TARGET_BRANCH/
- cp .domains $CI_REPO_NAME || true # Ignore if it doesn't exist
# Commit & Push
- cd $TARGET_BRANCH
- git add .
- git diff-index --quiet HEAD || git commit -m "$CI_COMMIT_MESSAGE"
- git push
```

but with [appleboy/drone-git-push](https://woodpecker-ci.org/plugins/Git%20Push)?

Start with the plugin's existing usage documentation and the linked Git Push page, then compare its options with the shown workflow. Document the equivalent configuration for building or copying a subdirectory to another branch and pushing only when changes exist; completion means a newcomer can follow the example for GitHub or CodeBerg Pages.

Written by the indexing model from the issue text.