all: remove unused dependencies

[Clivern]

Removed https://github.com/fatih/color and https://github.com/mattn/go-colorable since they are not used anymore inside wire. even https://github.com/fatih/color got archived and not maintained anymore.

[go-cloud-bot]

Please edit the title of this pull request with the name of the affected component, or "all", followed by a colon, followed by a short summary of the change.

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[Clivern]

@googlebot I signed it!

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[zombiezen]

LGTM, thanks!