[Umbrella] Release InLong 2.1.0

[justinwwhuang]

Describe the proposal

This proposal is going to release apache inlong 2.1.0(corresponding to milestone 2.1.0)

For history release like 2.0.0, refer to #11290

Task list

• [Release] Add the 2.1.0 version option for the bug report #11635
• [Release] Update changes log for the 2.1.0 version #11637
• [Release] Create a 2.1.0 branch to release #11639
• [Release] Bumped master branch version to 2.2.0-SNAPSHOT #11645
• [Release] Bumped version of branch-2.1.0 to 2.1.0 #11646
• [Release] Change the tag of Docker images to 2.1.0 #11647
• [Release] Publish all 2.1.0 images to docker hub #11649
• [Release] Modify download & release notes for 2.1.0 inlong-website#1094
• [Release] Create the 2.1.0 version document inlong-website#1095
• [Release] Add blog for the 2.1.0 release inlong-website#1096

InLong Component

Other for not specified component

Are you willing to submit PR?

• Yes, I am willing to submit a PR!

Code of Conduct

• I agree to follow this project's Code of Conduct