contributing: edited contributing file (#385)
contributing: edited contributing file (#385)

Included files that should be edited in order to generate the RSTs and DOCs when a new .proto is added to the project.

Signed-off-by: Gabriel <30d06b31ce38d95d8deab3affcfd5e152a121005@gmail.com>

jrajahalme/envoy-api,lyft/envoy-api,jrajahalme/envoy-api,jrajahalme/envoy-api,lyft/envoy-api,lyft/envoy-api,jrajahalme/envoy-api