Fix RELEASENOTES.md nesting.

RELEASENOTES.md

@@ -151,7 +151,7 @@
       ([#2149](https://github.com/google/ExoPlayer/issues/2149)).
       ([#2149](https://github.com/google/ExoPlayer/issues/2149)).
     * Avoid failure when expected ID3 header not found
     * Avoid failure when expected ID3 header not found
       ([#1966](https://github.com/google/ExoPlayer/issues/1966)).
       ([#1966](https://github.com/google/ExoPlayer/issues/1966)).
-* Improvements to the upstream cache package.
+   * Improvements to the upstream cache package.
     * Support caching of media segments for DASH, HLS and SmoothStreaming. Note
     * Support caching of media segments for DASH, HLS and SmoothStreaming. Note
       that caching of manifest and playlist files is still not supported in the
       that caching of manifest and playlist files is still not supported in the
       (normal) case where the corresponding responses are compressed.
       (normal) case where the corresponding responses are compressed.