Version 0.3.0

Changes to package errgroupx:

1. Added constructor funcs WithCancel, WithDeadline, and WithTimeout that wrap their similarly named funcs from the context package.
2. The constructor func New is now deprecated; the new WithCancel func does the same thing.
3. Renamed type GoFunc to ContextFunc.
4. Package docs updated accordingly.

Change to package pipeline:

1. Update the handling around Interface.Feed so that the Pipeline will take care of closing its associated channel and updated the docs accordingly. NOTE: This is a breaking change.
2. Add GoContext method for adding additional goroutine functions having a lifecycle associated with pipeline stages, yet is unrelated to any pipeline data.

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Full Changelog: v0.2.3...v0.3.0