Bump cygwin/cygwin-install-action from 3 to 4

Bumps [cygwin/cygwin-install-action](https://github.com/cygwin/cygwin-install-action) from 3 to 4.
- [Release notes](https://github.com/cygwin/cygwin-install-action/releases)
- [Commits](cygwin/cygwin-install-action@v3...v4)

---
updated-dependencies:
- dependency-name: cygwin/cygwin-install-action
  dependency-type: direct:production
  update-type: version-update:semver-major
...

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

Author: dependabot[bot]

.github/workflows/cygwin-test.yml

@@ -19,7 +19,7 @@ jobs:
     - uses: actions/checkout@v3
       with:
         fetch-depth: 9999
-    - uses: cygwin/cygwin-install-action@v3
+    - uses: cygwin/cygwin-install-action@v4
       with:
         packages: python39 python39-pip python39-virtualenv git
     - name: Tell git to trust this repo