Bump purcell/setup-emacs from 3.0 to 4.0 (#2005)

Bumps [purcell/setup-emacs](https://github.com/purcell/setup-emacs) from 3.0 to 4.0.
- [Release notes](https://github.com/purcell/setup-emacs/releases)
- [Commits](purcell/setup-emacs@v3.0...v4.0)

---
updated-dependencies:
- dependency-name: purcell/setup-emacs
  dependency-type: direct:production
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <[email protected]>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Author: dependabot[bot]

.github/workflows/emacs-test.yml

@@ -25,7 +25,7 @@ jobs:
         run: tools/azurePipelinesBuild.ps1
 
       - name: Install Emacs
-        uses: purcell/setup-emacs@v3.0
+        uses: purcell/setup-emacs@v4.0
         with:
           version: '28.1'