Fix licenses header in scaffolded files #146

[martinpeck]

This PR addresses the issue mentioned in #146.

There are two main changes:

1. I've updated the boilerplate.go.txt so that all future scaffolded files (generated by kubebuilder) will pick up the MIT license, with 2020 as the year for copyright.
2. I've replaced all of the existing files, created from the incorrect boilerplate, with the MIT license with 2019 (the year that the file header already stated) for the copyright.

I broke these two changes out into 2 separate commits.

The alternative approach is to set boilerplate.go.txt to be blank, and to clear the license headers across all files. I can do that if you'd rather.

[Azadehkhojandi]

Thank you

[Azadehkhojandi]

/azp run

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[Azadehkhojandi]

/azp run

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Azure Pipelines successfully started running 1 pipeline(s).