Export Key and Entity.

[vicb]

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Fixes #568 by exporting Key and Entity.

Tested: copied the generated .d.ts to one of my project and makes sure I can use the Key type.

[...]
import { Entities, entity, Entity, ValueProto } from './entity';
import Key = entity.Key;
export {Entity, Key};

[codecov]

Codecov Report

Merging #749 (2eb6692) into master (07a77fe) will increase coverage by 0.00%.
The diff coverage is 100.00%.

@@           Coverage Diff           @@
##           master     #749   +/-   ##
=======================================
  Coverage   98.94%   98.94%           
=======================================
  Files          11       11           
  Lines        7890     7893    +3     
  Branches      470      470           
=======================================
+ Hits         7807     7810    +3     
  Misses         81       81           
  Partials        2        2           

Impacted Files	Coverage Δ
src/index.ts	99.83% <100.00%> (+<0.01%)	⬆️

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[vicb]

@stephenplusplus anything missing from this PR to be mergeable ?

/cc @cgfrost

[stephenplusplus]

@vicb Sorry for the delay, LGTM! I'll wait out the CI and try to get this released today.

[vicb]

Thanks a lor @stephenplusplus