Upgrade the ubuntu image to 22.04 LTS

Change-Id: Id1a0be9f2dc17ea85114367c58761da8511db2ba
diff --git a/README.md b/README.md
index d648262..e1adfbf 100644
--- a/README.md
+++ b/README.md
@@ -42,7 +42,7 @@
 git checkout v3.3.0
 ```
 
-Navigate to either `./almalinux/8` or `./ubuntu/20` to build the almalinux- or ubuntu-based docker
+Navigate to either `./almalinux/8` or `./ubuntu/22` to build the almalinux- or ubuntu-based docker
 image, respectively. Then run:
 
 ```
diff --git a/ubuntu/20/.dockerignore b/ubuntu/22/.dockerignore
similarity index 100%
rename from ubuntu/20/.dockerignore
rename to ubuntu/22/.dockerignore
diff --git a/ubuntu/20/Dockerfile b/ubuntu/22/Dockerfile
similarity index 98%
rename from ubuntu/20/Dockerfile
rename to ubuntu/22/Dockerfile
index 7a6e058..6b29393 100644
--- a/ubuntu/20/Dockerfile
+++ b/ubuntu/22/Dockerfile
@@ -1,4 +1,4 @@
-FROM ubuntu:20.04
+FROM ubuntu:22.04
 MAINTAINER Gerrit Code Review Community
 
 # Add Gerrit packages repository
diff --git a/ubuntu/20/Dockerfile-dev b/ubuntu/22/Dockerfile-dev
similarity index 98%
rename from ubuntu/20/Dockerfile-dev
rename to ubuntu/22/Dockerfile-dev
index d6ceead..e261a73 100644
--- a/ubuntu/20/Dockerfile-dev
+++ b/ubuntu/22/Dockerfile-dev
@@ -1,4 +1,4 @@
-FROM ubuntu:20.04
+FROM ubuntu:22.04
 MAINTAINER Gerrit Code Review Community
 
 ARG GERRIT_WAR_URL="https://gerrit-ci.gerritforge.com/view/Gerrit/job/Gerrit-bazel-master/lastSuccessfulBuild/artifact/gerrit/bazel-bin/release.war"
diff --git a/ubuntu/20/entrypoint.sh b/ubuntu/22/entrypoint.sh
similarity index 100%
rename from ubuntu/20/entrypoint.sh
rename to ubuntu/22/entrypoint.sh