Docker: Upgrade to Ubuntu 20.04 in Dockerfiles (#23852)

* Chore: Upgrade to Ubuntu 20.04
Co-authored-by: Marcus Efraimsson <marcus.efraimsson@gmail.com>

packaging/docker/build.sh

@@ -64,7 +64,7 @@ docker_build () {
   else
     libc=""
     dockerfile="ubuntu.Dockerfile"
-    base_image="${base_arch}ubuntu:19.10"
+    base_image="${base_arch}ubuntu:20.04"
   fi
 
   grafana_tgz="grafana-latest.linux-${arch}${libc}.tar.gz"

packaging/docker/ubuntu.Dockerfile

@@ -1,4 +1,4 @@
-ARG BASE_IMAGE=ubuntu:19.10
+ARG BASE_IMAGE=ubuntu:20.04
 FROM ${BASE_IMAGE} AS grafana-builder
 
 ARG GRAFANA_TGZ="grafana-latest.linux-x64.tar.gz"