Include *.kt files in buildSrc in cache key

src/cache.ts

@@ -31,7 +31,7 @@ const supportedPackageManager: PackageManager[] = [
     id: 'gradle',
     path: [join(os.homedir(), '.gradle', 'caches'), join(os.homedir(), '.gradle', 'wrapper')],
     // https://github.com/actions/cache/blob/0638051e9af2c23d10bb70fa9beffcad6cff9ce3/examples.md#java---gradle
-    pattern: ['**/*.gradle*', '**/gradle-wrapper.properties']
+    pattern: ['**/*.gradle*', '**/gradle-wrapper.properties', 'buildSrc/**/*.kt']
   }
 ];