Merge pull request #988 from crawlab-team/develop

added changelog for v0.6.0-beta.20210803

changelog/v0.6.0-beta.20210803.md

@@ -8,7 +8,7 @@ This is the beta release for the next major version v0.6.0. **It recommended NOT
 
 As a major release, v0.6 (including beta versions) is consisted of a number of large changes to enhance the performance, scalability, robustness and usability of Crawlab. This beta version is theoretically more robust than older versions mainly in task execution, files synchronization and node management, yet we still recommend users to thoroughly run tests with various samples.
 
-####Backend
+#### Backend
 
 - **File Synchronization**. Migrated file sync from MongoDB GridFS to SeaweedFS for better stability and robustness.
 - **Node Communication**. Migrated node communication from Redis-based RPC to gRPC. Worker nodes indirectly interact with MongoDB by making gRPC calls to the master node.