bbi.sh v3.5.1:
Added support for BRANCH_SPEC, DEPOT_SPEC, and STREAM_SPEC
actions, which allow imports to use hand-crafted spec files
during imports.
This allows the BBI import process to simulate the evolution
of stream specs over time, e.g. to reflect reparenting,
and to account for things like non-branching files and CBD
workflows that use sophisticated, hand-crafted stream specs.
The required BBI Config file version has been updated from
3.2 to 3.5.
Test suite has been updated to test new functionality.