Dart 2.12.4 (#693)

diff --git a/.gitpod.Dockerfile b/.gitpod.Dockerfile
index a015f68..3dc738d 100644
--- a/.gitpod.Dockerfile
+++ b/.gitpod.Dockerfile
@@ -6,8 +6,8 @@
 # More information: https://www.gitpod.io/docs/config-docker/
 
 RUN sudo apt-get update && \
-    wget https://storage.googleapis.com/dart-archive/channels/stable/release/2.12.2/linux_packages/dart_2.12.2-1_amd64.deb && \
-    sudo dpkg -i dart_2.12.2-1_amd64.deb && \
+    wget https://storage.googleapis.com/dart-archive/channels/stable/release/2.12.4/linux_packages/dart_2.12.4-1_amd64.deb && \
+    sudo dpkg -i dart_2.12.4-1_amd64.deb && \
     sudo apt-get install -y protobuf-compiler redis && \
     sudo apt-get update && \
     echo "export PATH=\"\$PATH:/usr/lib/dart/bin:\$HOME/.pub-cache/bin\"" >> $HOME/.bashrc && \
diff --git a/cloud_run.Dockerfile b/cloud_run.Dockerfile
index 6de13f8..ce36db9 100644
--- a/cloud_run.Dockerfile
+++ b/cloud_run.Dockerfile
@@ -1,4 +1,4 @@
-FROM google/dart:2.12.2
+FROM google/dart:2.12.4
 
 # We install unzip and remove the apt-index again to keep the
 # docker image diff small.
diff --git a/cloud_run_null_safety.Dockerfile b/cloud_run_null_safety.Dockerfile
index c4205d0..854662f 100644
--- a/cloud_run_null_safety.Dockerfile
+++ b/cloud_run_null_safety.Dockerfile
@@ -1,4 +1,4 @@
-FROM google/dart:2.12.2
+FROM google/dart:2.12.4
 
 # We install unzip and remove the apt-index again to keep the
 # docker image diff small.