releng-ci: Build v0.5.2 image using go1.16.4

Signed-off-by: Stephen Augustus <[email protected]>

Author: justaugustus

images/releng/ci/cloudbuild.yaml

@@ -24,8 +24,8 @@ substitutions:
   # vYYYYMMDD-hash, and can be used as a substitution
   _GIT_TAG: '12345'
   _PULL_BASE_REF: 'dev'
-  _IMAGE_VERSION: 'v0.5.1'
-  _GO_VERSION: '1.16.3'
+  _IMAGE_VERSION: 'v0.5.2'
+  _GO_VERSION: '1.16.4'
   _REGISTRY: 'fake.repository/registry-name'
 images:
   - 'gcr.io/$PROJECT_ID/releng-ci:${_GIT_TAG}'