New options for encoding Go strings to and from CBOR byte strings

[benluddy]

Description

PR Was Proposed and Welcomed in Currently Open Issue

• This PR was proposed and welcomed by maintainer(s) in issue feature: Transparent encoding and decoding of Go strings to and from CBOR byte strings #446
• Closes or Updates Issue feature: Transparent encoding and decoding of Go strings to and from CBOR byte strings #446

Checklist (for code PR only, ignore for docs PR)

• Include unit tests that cover the new code
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[fxamacker]

This is great! 👍 Thanks for adding this useful feature and also for optimizing byte string decoding while at it!

I left some minor suggestions about naming conventions used by existing options, etc.

[fxamacker]

Suggested change

	// StringType specifies which CBOR string major type to use when encoding Go strings.
	StringType StringType
	// String specifies which CBOR type to use when encoding Go strings.
	// - CBOR text string (major type 3) is default
	// - CBOR byte string (major type 2)
	String StringMode

[benluddy]

Thanks @fxamacker, I've implemented all of your suggestions. Please take another look!

[fxamacker]

LGTM! 👍 Thanks again for this PR!