Re-formats for 2020 copyright

[rafaparadela]

I have another PR pending but I don't want to include the 2019/2020 changes in the code review.

[bond15]

Feel free to merge once travis approves.

[codecov]

Codecov Report

Merging #326 into master will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master     #326   +/-   ##
=======================================
  Coverage   87.85%   87.85%           
=======================================
  Files          37       37           
  Lines         700      700           
  Branches        5        5           
=======================================
  Hits          615      615           
  Misses         85       85

Impacted Files	Coverage Δ
...src/main/scala/github4s/free/algebra/GistOps.scala	0% <ø> (ø)	⬆️
github4s/src/main/scala/github4s/Implicits.scala	33.33% <ø> (ø)	⬆️
...main/scala/github4s/free/algebra/ActivityOps.scala	100% <ø> (ø)	⬆️
...cala/github4s/HttpRequestBuilderExtensionJVM.scala	100% <ø> (ø)	⬆️
...hub4s/src/main/scala/github4s/api/Activities.scala	100% <ø> (ø)	⬆️
...in/scala/github4s/free/algebra/RepositoryOps.scala	75% <ø> (ø)	⬆️
...n/scala/github4s/free/algebra/PullRequestOps.scala	81.81% <ø> (ø)	⬆️
github4s/src/main/scala/github4s/GithubAPIs.scala	100% <ø> (ø)	⬆️
...4s/src/main/scala/github4s/GithubDefaultUrls.scala	100% <ø> (ø)	⬆️
github4s/src/main/scala/github4s/Decoders.scala	96.26% <ø> (ø)	⬆️
... and 25 more

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