This behaves the same as defaultMain, but auto-generates Haskell files from .proto files which are:
Listed in the
.cabalfile underextra-source-files,Located under the given root directory, and
Correspond to a module (
"Proto.*") in `exposed-modules` or `other-modules` of some component in the.cabalfile.
Writes the generated files to the autogen directory (dist/build/autogen
for Cabal, and .stack-work/dist/.../build/autogen for stack).
Throws an exception if the proto-lens-protoc executable is not on the PATH.