cache master only (#233)

* cache master only

* cache downloaded aptos binaries

* try enabling cache to test

* disable zips caching

.github/workflows/check.yml

@@ -29,7 +29,7 @@ jobs:
                 uses: gradle/actions/setup-gradle@v4
                 with:
                     # with `true`, caches will only be created in `master` branch, and PRs will run read-only
-                    cache-read-only: false
+                    cache-read-only: true
 
             -   name: Build
                 run: ./gradlew assemble --stacktrace -Pkotlin.incremental=false