build(deps): bump cygwin/cygwin-install-action from 5 to 6

Bumps [cygwin/cygwin-install-action](https://github.com/cygwin/cygwin-install-action) from 5 to 6.
- [Release notes](https://github.com/cygwin/cygwin-install-action/releases)
- [Commits](cygwin/cygwin-install-action@v5...v6)

---
updated-dependencies:
- dependency-name: cygwin/cygwin-install-action
  dependency-version: '6'
  dependency-type: direct:production
  update-type: version-update:semver-major
...

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

Author: dependabot[bot]

.github/workflows/test.yml

@@ -53,7 +53,7 @@ jobs:
           submodules: true
 
       - name: Set up Cygwin
-        uses: cygwin/cygwin-install-action@v5
+        uses: cygwin/cygwin-install-action@v6
         with:
           packages: >-
             make