Add roadmap badge in README

[bowenlan-amzn]

Signed-off-by: bowenlan-amzn bowenlan23@gmail.com

Issue #, if available:

Description of changes:

CheckList:

• Commits are signed per the DCO using --signoff

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[codecov-commenter]

Codecov Report

Merging #295 (bacb823) into main (7d5d2fb) will increase coverage by 0.16%.
The diff coverage is n/a.

@@             Coverage Diff              @@
##               main     #295      +/-   ##
============================================
+ Coverage     76.30%   76.47%   +0.16%     
+ Complexity     2046     2045       -1     
============================================
  Files           262      262              
  Lines         11848    11848              
  Branches       1887     1887              
============================================
+ Hits           9041     9061      +20     
+ Misses         1783     1757      -26     
- Partials       1024     1030       +6     

Impacted Files	Coverage Δ
...nt/indexstatemanagement/model/destination/Chime.kt	40.90% <0.00%> (-13.64%)	⬇️
...rch/indexmanagement/rollup/model/RollupMetadata.kt	82.73% <0.00%> (-1.79%)	⬇️
...management/indexstatemanagement/MetadataService.kt	61.15% <0.00%> (-0.83%)	⬇️
.../opensearch/indexmanagement/rollup/model/Rollup.kt	83.96% <0.00%> (-0.48%)	⬇️
...nt/indexstatemanagement/ManagedIndexCoordinator.kt	72.11% <0.00%> (+0.32%)	⬆️
...earch/indexmanagement/transform/TransformRunner.kt	86.42% <0.00%> (+0.71%)	⬆️
...ent/indexstatemanagement/util/ManagedIndexUtils.kt	79.91% <0.00%> (+1.22%)	⬆️
.../rollup/action/start/TransportStartRollupAction.kt	69.76% <0.00%> (+2.32%)	⬆️
...arch/indexmanagement/rollup/RollupSearchService.kt	59.25% <0.00%> (+3.70%)	⬆️
...statemanagement/model/destination/CustomWebhook.kt	92.75% <0.00%> (+27.53%)	⬆️

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[dbbaughe]

Make sure it stays updated now :P

[bowenlan-amzn]

Make sure it stays updated now :P

Using public to force us keep updating 😛