message: ci: use YAML references to define the build-image sha once
diff: -# TODO(mattklein123): See if there is a way to put build SHA into a variable.
  -# In the meantime, it's required to edit the SHA in this file as well as envoy_build_sha.sh.
  +references:
  + envoy-build-image: &envoy-build-image
  + envoyproxy/envoy-build:516cdcd55326648978f8db1fe3a774ec759f5a13
  version: 2
  jobs:
  release:
  docker:
  - - image: envoyproxy/envoy-build:516cdcd55326648978f8db1fe3a774ec759f5a13
  + - image: *envoy-build-image
  resource_class: xlarge
  working_directory: /source
  steps:
  @@ -16,7 +17,7 @@ jobs:
  - run: ci/docker_tag.sh
  asan:
  docker:
  - - image: envoyproxy/envoy-build:516cdcd55326648978f8db1fe3a774ec759f5a13
  + - image: *envoy-build-image
  resource_class: xlarge
  working_directory: /source
  steps:
  @@ -24,7 +25,7 @@ jobs:
  - run: ci/do_circle_ci.sh bazel.asan
  tsan:
  docker:
  - - image: envoyproxy/envoy-build:516cdcd55326648978f8db1fe3a774ec759f5a13
  + - image: *envoy-build-image
  resource_class: xlarge
  working_directory: /source
  steps:
  @@ -32,7 +33,7 @@ jobs:
  - run: ci/do_circle_ci.sh bazel.tsan
  coverage:
  docker:
  - - image: envoyproxy/envoy-build:516cdcd55326648978f8db1fe3a774ec759f5a13
  + - image: *envoy-build-image
  resource_class: xlarge
  working_directory: /source
  steps:
  @@ -43,7 +44,7 @@ jobs:
  path: /build/envoy/generated/coverage
  format:
  docker:
  - - image: envoyproxy/envoy-build:516cdcd55326648978f8db1fe3a774ec759f5a13
  + - image: *envoy-build-image
  resource_class: small
  working_directory: /source
  steps:
  