Fix ProtoBuf mapping.json

[StefH]

close #1233

[codecov]

Codecov Report

Attention: Patch coverage is 0% with 3 lines in your changes missing coverage. Please review.

Project coverage is 34.94%. Comparing base (9c94324) to head (0d5fb07).
Report is 2 commits behind head on master.

Files with missing lines	Patch %	Lines
...eMock.Net/ResponseBuilders/Response.WithHeaders.cs	0.00%	3 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #1236      +/-   ##
==========================================
+ Coverage   34.43%   34.94%   +0.50%     
==========================================
  Files         203      203              
  Lines       33320    33729     +409     
==========================================
+ Hits        11473    11785     +312     
- Misses      21331    21384      +53     
- Partials      516      560      +44     

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.