message: [build-utils] Add `repoRootPath` to `PrepareCacheOptions`
  `repoRootPath` is provided to the `prepareCache()` function and is the same value as provided to the `build()` function.
  Also remove `cachePath` since it's no longer used.
diff: @@ -119,10 +119,11 @@ export interface PrepareCacheOptions {
  workPath: string;
  /**
  - * A writable temporary directory where you can build a cache to use for
  - * the next run.
  + * The "Root Directory" is assigned to the `workPath` so the `repoRootPath`
  + * is the Git Repository Root. This is only relevant for Monorepos.
  + * See https://vercel.com/blog/monorepos
  */
  - cachePath: string;
  + repoRootPath?: string;
  /**
  * An arbitrary object passed by the user in the build definition defined
  