grpc-httpjson-transcode: Update for RFC2045 support (#8065)

RFC2045 (MIME) Base64 decoding support has been fixed upstream

Description: The grpc transcoding filter has been updated to support RFC2045 (MIME) based inputs for protobuf type "Bytes". This is important since Base64 is often using the RFC2045 format for inputs.
Also see: grpc-ecosystem/grpc-httpjson-transcoding#34

Risk Level: Low
Testing: Integration / Manual Tests
Docs Changes: N/A
Release Notes: N/A

Signed-off-by: Hans Viken Duedal <hans.duedal@visma.com>

bazel/repository_locations.bzl

@@ -212,10 +212,10 @@ REPOSITORY_LOCATIONS = dict(
         urls = ["https://github.com/protocolbuffers/protobuf/releases/download/v3.8.0/protobuf-all-3.8.0.tar.gz"],
     ),
     grpc_httpjson_transcoding = dict(
-        sha256 = "dedd76b0169eb8c72e479529301a1d9b914a4ccb4d2b5ddb4ebe92d63a7b2152",
-        strip_prefix = "grpc-httpjson-transcoding-64d6ac985360b624d8e95105701b64a3814794cd",
-        # 2018-12-19
-        urls = ["https://github.com/grpc-ecosystem/grpc-httpjson-transcoding/archive/64d6ac985360b624d8e95105701b64a3814794cd.tar.gz"],
+        sha256 = "a447458b47ea4dc1d31499f555769af437c5d129d988ec1e13d5fdd0a6a36b4e",
+        strip_prefix = "grpc-httpjson-transcoding-2feabd5d64436e670084091a937855972ee35161",
+        # 2019-08-28
+        urls = ["https://github.com/grpc-ecosystem/grpc-httpjson-transcoding/archive/2feabd5d64436e670084091a937855972ee35161.tar.gz"],
     ),
     io_bazel_rules_go = dict(
         sha256 = "96b1f81de5acc7658e1f5a86d7dc9e1b89bc935d83799b711363a748652c471a",