feat(member API): exact dates

[ryparker]

It would be nice to have the exact year, month, and day of the following member dates:

• birthDate
• deathDate
• terms - startDate
• terms - endDate
• partyHistory - startDate
• partyHistory - endDate

Currently only the year is returned for these dates.

[rbram]

Hello. Thanks for your question. The Congressional BioGuide is the official source for this information. https://bioguide.congress.gov/search