Fix "cabal check" on proto-lens-protobuf-types. (#360)
Fix "cabal check" on proto-lens-protobuf-types. (#360)

This was preventing us from uploading the package to Hackage.
It was caused by #353 which (as expected) bumped the .cabal
file to require version 2.  Unfortunately, this ran afoul
of an hpack issue:
https://github.com/sol/hpack/issues/303

Specifically: (a) hpack auto-adds a `Paths_*`
module, and (b) Cabal v2 expects that to be listed explicitly
in `autogen-modules`, which hpack does not do.

Work around this by following a suggestion from the above thread:
include an explicit `verbatim`/`other-modules` clause,
which prevents hpack from auto-adding the `Paths_*` module.
google/proto-lens