docs: add example customizing unmarshal options (#1335)
docs: add example customizing unmarshal options (#1335)

* docs: add example customizing unmarshal options

Signed-off-by: Stephan Renatus <3d1a7d0a294b6d8e799ad6e122143905f17f9530@chef.io>

* Update docs/_docs/customizingyourgateway.md

Signed-off-by: Stephan Renatus <3d1a7d0a294b6d8e799ad6e122143905f17f9530@chef.io>

Co-authored-by: Johan Brandhorst <8c98250619a5229afaab52d25e022b9e3e1d22a2@gmail.com>

Co-authored-by: Johan Brandhorst <8c98250619a5229afaab52d25e022b9e3e1d22a2@gmail.com>
gengo/grpc-gateway,grpc-ecosystem/grpc-gateway,gengo/grpc-gateway