feat: add releaseDate to json

[marco-ippolito]

Fixes: https://github.com/nodejs-private/security-release/issues/23

@RafaelGSS

[RafaelGSS]

actually, we need to check if a valid date is given, if not it should leave it empty. For instance, TBD.

[marco-ippolito]

actually, we need to check if a valid date is given, if not it should leave it empty. For instance, TBD.

if invalid date is given it will throw right now

[RafaelGSS]

actually, we need to check if a valid date is given, if not it should leave it empty. For instance, TBD.

if invalid date is given it will throw right now

But, what if we don't have a target date? I would like to pass TBD

[marco-ippolito]

ok so I'll validate only if different from 'TBD'