Upgrade all Docker images to latest. (#2621)

Un-pin from the Xenial revision.

Author: oliverchang

docker/chromium/base/Dockerfile

@@ -11,7 +11,7 @@
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
-FROM gcr.io/clusterfuzz-images/base@sha256:1110514de5bb678562b75e5cf65130923bd22bb9371dcbc9e99483fd277ac135
+FROM gcr.io/clusterfuzz-images/base
 
 ENV UPDATE_WEB_TESTS True
 ENV NFS_ROOT /mnt/nfs/cfvolume

docker/chromium/builder/Dockerfile

@@ -11,7 +11,7 @@
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
-FROM gcr.io/clusterfuzz-images/base@sha256:1110514de5bb678562b75e5cf65130923bd22bb9371dcbc9e99483fd277ac135
+FROM gcr.io/clusterfuzz-images/base
 
 ENV RUN_CMD \
    "python3.7 $ROOT_DIR/src/python/other-bots/chromium-builder/run.py"

docker/chromium/tests-syncer/Dockerfile

@@ -11,7 +11,7 @@
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
-FROM gcr.io/clusterfuzz-images/base@sha256:1110514de5bb678562b75e5cf65130923bd22bb9371dcbc9e99483fd277ac135
+FROM gcr.io/clusterfuzz-images/base
 
 ENV RUN_CMD \
     "python3.7 $ROOT_DIR/src/python/other-bots/chromium-tests-syncer/run.py"

docker/fuchsia/Dockerfile

@@ -11,7 +11,7 @@
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
-FROM gcr.io/clusterfuzz-images/base@sha256:1110514de5bb678562b75e5cf65130923bd22bb9371dcbc9e99483fd277ac135
+FROM gcr.io/clusterfuzz-images/base
 
 RUN apt-get update && apt-get install -y openssh-client
 

docker/ml-with-gpu/Dockerfile

@@ -11,7 +11,7 @@
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
-FROM gcr.io/clusterfuzz-images/base@sha256:1110514de5bb678562b75e5cf65130923bd22bb9371dcbc9e99483fd277ac135
+FROM gcr.io/clusterfuzz-images/base
 
 WORKDIR /data