Remove fuzzit

It seems this service has been shut down and
migrated to GitLab.

Author: johanbrandhorst

.circleci/config.yml

@@ -79,14 +79,6 @@ jobs:
       - checkout
       - generate
       - run: git diff --exit-code
-  fuzzit:
-    docker:
-      - image: fuzzitdev/fuzzit:golang1.12-stretch-llvm9
-    working_directory: /src/grpc-gateway
-    steps:
-      - checkout
-      - setup_remote_docker
-      - run: ./fuzzit.sh
   bazel:
     executor: build-env
     working_directory: /src/grpc-gateway
@@ -166,7 +158,6 @@ workflows:
     jobs:
       - build
       - test
-      - fuzzit
       - node_test
       - generate
       - bazel