feat: Add disable_nojekyll and cname options (#119)

* feat: Add disable_nojekyll and cname options
* docs: Add cname and disable_nojekyll
* chore: Add vim
* chore(release): 3.3.0-0
* ci: Add codecov/codecov-action
* refactor: Enhance warning message

- Add .nojekyll file by default to only the master and gh-pages branches. When the file already exists, this action does nothing.
- When we set other branches to publish_branch, this action does not add .nojekyll file.

cf. https://github.com/peaceiris/actions-gh-pages/issues/112#issuecomment-589678269

Close #112

Co-authored-by: Daniel Himmelstein <daniel.himmelstein@gmail.com>
Co-authored-by: Nicolas Vanhoren <nicolas.vanhoren@gmail.com>

package.json

@@ -1,6 +1,6 @@
 {
   "name": "actions-github-pages",
-  "version": "3.2.0",
+  "version": "3.3.0-0",
   "description": "GitHub Actions for GitHub Pages",
   "main": "lib/index.js",
   "engines": {