Add decoding option TimeTagToAny to produce RFC3339 when decoding time into interface{}

[ssuriyan7]

Adds a decoding option to specify how to decode CBOR tag 0 or 1 data item into an empty interface. Based on the specified mode, Unmarshal can return a time.Time value or a time string in a specific format.

Description

PR Was Proposed and Welcomed in Currently Open Issue

• [x] This PR was proposed and welcomed by maintainer(s) in issue #496
• [x] Closes or Updates Issue #496

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

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

@ssuriyan7 Thanks for opening this PR! I'll try to take a look this week/weekend. :pray:

[ssuriyan7]

@fxamacker , Thanks for your suggestion. I've incorporated them. Please take a look.