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

[ssuriyan7]

Is your feature request related to a problem? Please describe.
When decoding a cbor data item, tagged with either tag 0 or tag 1, into an empty interface type, unmarshal returns a value of type time.Time. I would like a new decoding option with which unmarshal returns a RFC3339 string. This is needed to ensure compatibility in a project which expects unmarshal to return only certain types (bool, float64, string, []interface{}, map[string]interface{}, or nil).

Describe the solution you'd like
A new decode Option TimeTagToAnyMode whose default mode TimeTagToGoTime returns a time.Time value (current behavior). TimeTagToRFC3339String returns a time string in RFC3339 format and TimeTagToRFC3339NanoString returns a time string with nano seconds in RFC3339 format.

Additional context
I'd be happy to contribute the changes needed for this feature.

[fxamacker]

Hey @ssuriyan7 thanks for opening this feature request!

Please feel free to open a PR to implement TimeTagToAnyMode decoding option. Maybe with these option names:

• TimeTagToTime
• TimeTagToRFC3339
• TimeTagToRFC3339Nano

[ssuriyan7]

Waiting for #503 to merge as this option should be implemented on top of that change.

[fxamacker]

Hey @ssuriyan7 the PR got merged tonight:

• Decouple time.Time parsing from empty interface behavior. #503

[fxamacker]

Closed by #506