bump version to 2.2.0-SNAPSHOT

[nobodyiam]

What's the purpose of this PR

bump version to 2.2.0-SNAPSHOT

Brief changelog

• Upgrade version in pom.xml
• Move 2.1.0 changes to changes/changes-2.1.0.md
• Fix the Maven Central Repo svg to apollo-client.svg

Follow this checklist to help us incorporate your contribution quickly and easily:

• Read the Contributing Guide before making this pull request.
• Write a pull request description that is detailed enough to understand what the pull request does, how, and why.
• Write necessary unit tests to verify the code.
• Run mvn clean test to make sure this pull request doesn't break anything.
• Update the CHANGES log.

[codecov]

Codecov Report

Merging #4721 (3475886) into master (e773940) will not change coverage.
The diff coverage is n/a.

@@            Coverage Diff            @@
##             master    #4721   +/-   ##
=========================================
  Coverage     47.22%   47.22%           
  Complexity     1661     1661           
=========================================
  Files           349      349           
  Lines         10691    10691           
  Branches       1062     1062           
=========================================
  Hits           5049     5049           
  Misses         5335     5335           
  Partials        307      307           

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