Bump andstor/file-existence-action from 1 to 3

Bumps [andstor/file-existence-action](https://github.com/andstor/file-existence-action) from 1 to 3.
- [Release notes](https://github.com/andstor/file-existence-action/releases)
- [Commits](andstor/file-existence-action@v1...v3)

---
updated-dependencies:
- dependency-name: andstor/file-existence-action
  dependency-version: '3'
  dependency-type: direct:production
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <support@github.com>

Author: dependabot[bot]

.github/workflows/deploy.yml

@@ -30,7 +30,7 @@ jobs:
       # if e.g. composer install fails.
       - name: Check ConvertKit Library Exists
         id: check_files
-        uses: andstor/file-existence-action@v1
+        uses: andstor/file-existence-action@v3
         with:
           files: "vendor/convertkit/convertkit-wordpress-libraries/src/class-convertkit-api-traits.php, vendor/convertkit/convertkit-wordpress-libraries/src/class-convertkit-api-v4.php, vendor/convertkit/convertkit-wordpress-libraries/src/class-convertkit-log.php, vendor/convertkit/convertkit-wordpress-libraries/src/class-convertkit-resource-v4.php, vendor/convertkit/convertkit-wordpress-libraries/src/class-convertkit-review-request.php"