Add optional url field to _BaseVersion

[machow]

Currently, R pins adds a url field to the meta$local result of pin_meta for these boards:

• board_rsconnect
• board_url

Let's add an optional URL field high up in the version hierarchy, so that boards can tack it on as supplemental info. This is used by vetiver R in its rapidoc API spec.

[isabelizimm]

When the url is added (probably in a local data structure like R), can we add the GUID too? R currently stores this as well. And, as a plus, it would get rstudio/vetiver-python#96 nearly solved 😄

[machow]

Some examples:

R S3

R RSC

python RSC

Note that python pins includes version directly in metadata (rather than in metadata$local). VersionRaw only contains a version field (whereas Version includes version, created, and hash).

from dotenv import load_dotenv
load_dotenv()
from pins import board_rsconnect
board = board_rsconnect("https://colorado.rstudio.com/rsc")
board.pin_meta("mtcars3")

Meta(
    title='mtcars3: a pinned 32 x 11 DataFrame', description=None, created='20220624T122220Z', 
    pin_hash='3b134bae183b50c9', file='mtcars3.csv', file_size=1333, type='csv', api_version=1, 
    version=VersionRaw(version='58083'), name='michael.chow/mtcars3', user={}
)

[isabelizimm]

possibility to use lru cache to achieve this? rather than _user_name_cache

[isabelizimm]

implemented in #167