Bump coursier/cache-action from v5 to v6

Bumps [coursier/cache-action](https://github.com/coursier/cache-action) from v5 to v6.
- [Release notes](https://github.com/coursier/cache-action/releases)
- [Commits](coursier/cache-action@v5...730a6a4)

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

.github/workflows/ci.yml

@@ -19,7 +19,7 @@ jobs:
     - uses: olafurpg/setup-scala@v10
       with:
         java-version: "adopt@1.${{ matrix.java }}"
-    - uses: coursier/cache-action@v5
+    - uses: coursier/cache-action@v6
     - run: sbt -v
            scalafmtCheckAll
            scalafmtSbtCheck