TiKV-CDC v1.1.1

Improvements

1. Fix memory leak.
2. Improve integration test rubustness.

What's Changed

• [close #328] cdc: simplify readme by @pingyu in #327
• [close #333] update client-go version to fix context leak by @pingyu in #332
• [close #334] tests: fix timeout of integration test sigstop by @pingyu in #335
• [close #333] Fix context leak in BatchDelete by @pingyu in #336