Fix wrong content type in protobuf plugin 0.5

[tienvx]

Fix this error if using protobuf plugin version 0.5 (not sure about 0.4)

expected a body of 'application/protobuf;message=.library.Person' but the actual content type was 'application/protobuf;message=Person'

I guess the .library. and .plugins. prefixes come from the package library; and package plugins; in proto files.

Depend on #622

[coveralls]

Pull Request Test Coverage Report for Build 10614134265

Details

• 0 of 0 changed or added relevant lines in 0 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage remained the same at 97.313%

---

Totals
Change from base Build 10611257072:	0.0%
Covered Lines:	2282
Relevant Lines:	2345

---

💛 - Coveralls

[YOU54F]

yep issue is from 0.5.0 onwards following an update

https://github.com/pactflow/pact-protobuf-plugin/releases/tag/v-0.5.0