Include 'generated by' header

[Alma-media]

Related to #134

(also includes fix for broken openapi3 generator)

// Code generated by Semaphore. DO NOT EDIT.
// Semaphore version: not set
// Timestamp: Wed, 04 Nov 2020 20:01:44 GMT
syntax = "proto2";

package semaphore.greeter;

message SayHelloRequest {
  optional string name = 1;
}

message SayHelloResponse {
  optional string msg = 1;

  optional metaNested meta = 2;

  message metaNested {
    optional int64 session = 1;
  }
}

service Say {
  rpc Hello ( SayHelloRequest ) returns ( SayHelloResponse );
}

[codecov-io]

Codecov Report

Merging #164 into master will decrease coverage by 0.11%.
The diff coverage is 79.66%.

@@            Coverage Diff             @@
##           master     #164      +/-   ##
==========================================
- Coverage   82.23%   82.12%   -0.12%     
==========================================
  Files         144      147       +3     
  Lines        6385     6463      +78     
==========================================
+ Hits         5251     5308      +57     
- Misses        761      775      +14     
- Partials      373      380       +7     

Impacted Files	Coverage Δ
pkg/transport/graphql/graphql.go	66.01% <0.00%> (-0.65%)	⬇️
cmd/semaphore/generate/printer/header.go	33.33% <33.33%> (ø)
pkg/codec/json/json.go	75.67% <50.00%> (+0.67%)	⬆️
pkg/transport/http/caller.go	75.22% <55.55%> (-2.56%)	⬇️
pkg/providers/schemas.go	73.82% <86.66%> (ø)
pkg/references/referenced.go	91.52% <91.52%> (ø)
pkg/generators/openapi3/generator.go	91.36% <100.00%> (+0.52%)	⬆️
pkg/generators/openapi3/options.go	100.00% <100.00%> (ø)
pkg/transport/http/http.go	33.33% <100.00%> (-24.25%)	⬇️
pkg/transport/http/proxy.go	50.00% <0.00%> (-50.00%)	⬇️
... and 3 more