Support CDDL bareword member key syntax for maps

[adpjhu]

It appears that the CDDL parser can only identify member keys of maps in CDDL when they have double quotes. The spec document section linked below allows for member keys without double quotes followed by a colon.

https://cbor-wg.github.io/cddl/draft-ietf-cbor-cddl.html#structs

[oyvindronningstad]

Thanks for the report, it's now tracked internally. In the meantime, the workaround is (as you are probably aware) to use quotes and =>:

{
    "literal_tstr_key" => my_value
}

[oyvindronningstad]

@adpjhu Bareword support is in PR #292. You're welcome to leave a review.