Add version to health endpoint.

[winder]

Summary

Add version to health endpoint.

Test Plan

Unit test.

[codecov-commenter]

Codecov Report

Merging #756 (695c97e) into develop (986705e) will increase coverage by 0.32%.
The diff coverage is 100.00%.

@@             Coverage Diff             @@
##           develop     #756      +/-   ##
===========================================
+ Coverage    54.85%   55.17%   +0.32%     
===========================================
  Files           27       27              
  Lines         3814     3815       +1     
===========================================
+ Hits          2092     2105      +13     
+ Misses        1450     1435      -15     
- Partials       272      275       +3     

Impacted Files	Coverage Δ
api/handlers.go	20.83% <100.00%> (+2.65%)	⬆️
api/pointer_utils.go	81.57% <0.00%> (+5.26%)	⬆️

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