Adds release notes for 2.0.0

[downsrob]

Signed-off-by: Clay Downs [email protected]

Issue #, if available:
#352

Description of changes:
Adds release notes for 2.0.0

CheckList:

• Commits are signed per the DCO using --signoff

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.
For more information on following Developer Certificate of Origin and signing off your commits, please check here.

[codecov-commenter]

Codecov Report

Merging #367 (ab4d0ec) into main (a7fd6c4) will increase coverage by 0.28%.
The diff coverage is n/a.

@@             Coverage Diff              @@
##               main     #367      +/-   ##
============================================
+ Coverage     75.09%   75.38%   +0.28%     
- Complexity     2135     2159      +24     
============================================
  Files           262      263       +1     
  Lines         12444    12413      -31     
  Branches       1966     1974       +8     
============================================
+ Hits           9345     9357      +12     
+ Misses         2028     1971      -57     
- Partials       1071     1085      +14     

Impacted Files	Coverage Δ
...nt/indexstatemanagement/ManagedIndexCoordinator.kt	69.29% <0.00%> (-5.94%)	⬇️
...arch/indexmanagement/rollup/RollupSearchService.kt	57.40% <0.00%> (-3.71%)	⬇️
.../rollup/action/start/TransportStartRollupAction.kt	72.94% <0.00%> (-2.36%)	⬇️
.../action/explain/TransportExplainTransformAction.kt	70.78% <0.00%> (-2.25%)	⬇️
...ent/indexstatemanagement/step/shrink/ShrinkStep.kt	36.26% <0.00%> (ø)
...earch/indexmanagement/transform/model/Transform.kt	85.89% <0.00%> (+0.42%)	⬆️
...ndexstatemanagement/IndexStateManagementHistory.kt	80.00% <0.00%> (+1.37%)	⬆️
...ent/indexstatemanagement/util/ManagedIndexUtils.kt	77.87% <0.00%> (+1.53%)	⬆️
...management/indexstatemanagement/MetadataService.kt	64.92% <0.00%> (+2.23%)	⬆️
...gement/indexstatemanagement/action/ShrinkAction.kt	70.58% <0.00%> (+2.94%)	⬆️
... and 7 more

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