Add PATCH method for Fuel

[kittinunf]

What's in this PR?

This PR mitigates the issue where Fuel don't expose PATCH method for client to use. This PR will remedy that.

Merging this should close #133

[babedev]

Something wrong with tests?

[kittinunf]

It seems like httpbin.org doesn't support POST method for www.httpbin.org/patch endpoint. 😿

[codecov]

Codecov Report

Merging #156 into master will increase coverage by 1.13%.
The diff coverage is 100%.

@@             Coverage Diff              @@
##             master     #156      +/-   ##
============================================
+ Coverage     60.72%   61.85%   +1.13%     
- Complexity      145      161      +16     
============================================
  Files            29       29              
  Lines           802      852      +50     
  Branches        143      158      +15     
============================================
+ Hits            487      527      +40     
- Misses          229      232       +3     
- Partials         86       93       +7

Impacted Files	Coverage Δ	Complexity Δ
...n/kotlin/com/github/kittinunf/fuel/core/Request.kt	63.15% <ø> (+0.78%)	51 <0> (+9)	⬆️
.../src/main/kotlin/com/github/kittinunf/fuel/Fuel.kt	85.36% <100%> (+1.58%)	1 <0> (ø)	⬇️
...in/com/github/kittinunf/fuel/toolbox/HttpClient.kt	72.41% <100%> (+0.48%)	17 <0> (+2)	⬆️
.../kittinunf/fuel/core/requests/UploadTaskRequest.kt	79.59% <0%> (+7.36%)	12% <0%> (+5%)	⬆️
...kotlin/com/github/kittinunf/fuel/util/Delegates.kt	83.33% <0%> (+16.66%)	0% <0%> (ø)	⬇️

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[kittinunf]

🎉 🎉 🎉

[babedev]

Wow, let's merge this.