How to support Data Package versions and version changes in frictionless-r

[peterdesmet]

Data Package is now versioned, something that can be indicated at the $schema property. Ideally, frictionless-r supports (the properties that makes sense) for all versions (currently v1 and v2) and doesn't require users to install an older version of frictionless-r to support previous versions of Data Package

Reading

Ideally, when reading a data package, frictionless-r:

• Detects the version of package, resource, dialect, schema
• Assumes v1 if not provided in schema (cf. specs)
• Does not communicate version, but can provided it with detected function version()
• Silently (!) ignores properties that are not part of the version (e.g. categorical in v1): note, this may be frustrating to the user, who should know to update $schema to v2, but warning for all of these is hard to provide.
• Warns if a version is not recognized and reverts to the latest version supported by frictionless-r

Writing

Ideally, when writing a data package, frictionless-r:

• Always writes to the latest version supported by frictionless-r? This can be frustrating to users who want to retain the version.
• Alternatively, write_package() allows to specify a version, and older versions can be gradually phased out.

Examples and test

• Update example to v2
• Provide test files for v1