chore(deps): update docker.io/library/ubuntu docker tag to v26

Dockerfile

@@ -1,6 +1,6 @@
-FROM docker.io/library/ubuntu:24.04 AS download
+FROM docker.io/library/ubuntu:26.04 AS download
 
-ARG DC_VERSION=v5.1.2
+ARG DC_VERSION=v5.1.3
 
 RUN NAME=docker-compose-$(uname | tr [:upper:] [:lower:])-$(uname -m); \
     apt update --yes && \

README.md

@@ -11,7 +11,7 @@ The workflow or how `docker-compose` can in general be used is documented at
 image.
 
 ```bash
-IMAGE_VERSION=5.1.2
+IMAGE_VERSION=5.1.3
 docker run \
   --rm \
   --volume "$(pwd):$(pwd)" \