fix: Support enums in proto HTTP annotations [ggj]

[miraleung]

No description provided.

[codecov]

Codecov Report

Merging #733 (dc155c8) into master (f44df21) will decrease coverage by 0.00%.
The diff coverage is 0.00%.

@@            Coverage Diff             @@
##           master     #733      +/-   ##
==========================================
- Coverage   92.04%   92.04%   -0.01%     
==========================================
  Files         124      124              
  Lines       13531    13531              
  Branches     1005     1006       +1     
==========================================
- Hits        12455    12454       -1     
  Misses        823      823              
- Partials      253      254       +1     

Impacted Files	Coverage Δ
...pi/generator/gapic/protoparser/HttpRuleParser.java	85.71% <0.00%> (-1.43%)	⬇️

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[vam-google]

LGTM.
Can we also add a test for it? Only if it can be done with little effort, please do not add the full set of new test just for this feature (really not worth it).

[miraleung]

LGTM.
Can we also add a test for it? Only if it can be done with little effort, please do not add the full set of new test just for this feature (really not worth it).

Clicked merge too soon, will look into this as a followup.