encoding/protobuf: always include type as second argument
This significanty simplifies finding the right mapping from
CUE to protobuf.
Also changed map type from map<A,B> to map[A]B. The former
caused issues as the comma caused it to be a separate
attribute argument (<> is not matched). Encosing it in
quotes was also annoying.
We considered using [A]:B, but using the map notation allows
for more extendibility and less ambiguity in case we must
support lists for some reason.
This is a backwards incompatible change.
Issue #5
Change-Id: Ief64d0c91d481fd7b03a4a8842faf377fd364a26
Reviewed-on: https://cue-review.googlesource.com/c/cue/+/9368
Reviewed-by: Marcel van Lohuizen <mpvl@golang.org>
Reviewed-by: CUE cueckoo <cueckoo@gmail.com>
Reviewed-by: Paul Jolly <paul@myitcv.org.uk>