chore: Use Ubuntu 26.04 (resolute) for devcontainer

Author: tpoliaw

template/Dockerfile.jinja

@@ -1,6 +1,6 @@
 # The devcontainer should use the developer target and run as root with podman
 # or docker with user namespaces.
-FROM ghcr.io/diamondlightsource/ubuntu-devcontainer:noble AS developer
+FROM ghcr.io/diamondlightsource/ubuntu-devcontainer:resolute AS developer
 
 # Add any system dependencies for the developer/build environment here
 RUN apt-get update -y && apt-get install -y --no-install-recommends \