openEO Python Client v0.31.0

Added

• Add experimental openeo.testing.results subpackage with reusable test utilities for comparing batch job results with reference data
• MultiBackendJobManager: add initial support for storing job metadata in Parquet file (instead of CSV) (#571)
• Add Connection.authenticate_oidc_access_token() to set up authorization headers with an access token that is obtained "out-of-band" (#598)
• Add JobDatabaseInterface to allow custom job metadata storage with MultiBackendJobManager (#571)