Upgrade devture/ansible and note that it also includes agru now

Ref https://github.com/devture/docker-ansible/issues/2

docs/ansible.md

@@ -31,7 +31,10 @@ If using the `pip` method, do note that the `ansible-playbook` binary may not be
 
 Alternatively, you can run Ansible inside a Docker container (powered by the [devture/ansible](https://hub.docker.com/r/devture/ansible/) Docker image).
 
-This ensures that you're using a very recent Ansible version, which is less likely to be incompatible with the playbook.
+This ensures that:
+
+- you're using a very recent Ansible version, which is less likely to be incompatible with the playbook
+- you also get access to the [agru](https://github.com/etkecc/agru) tool for quicker Ansible role installation (when running `just roles`) compared to `ansible-galaxy`
 
 You can either [run Ansible in a container on the Matrix server itself](#running-ansible-in-a-container-on-the-matrix-server-itself) or [run Ansible in a container on another computer (not the Matrix server)](#running-ansible-in-a-container-on-another-computer-not-the-matrix-server).
 
@@ -57,7 +60,7 @@ docker run -it --rm \
 -w /work \
 -v `pwd`:/work \
 --entrypoint=/bin/sh \
-docker.io/devture/ansible:2.18.1-r0-0
+docker.io/devture/ansible:2.18.1-r0-2
 ```
 
 Once you execute the above command, you'll be dropped into a `/work` directory inside a Docker container. The `/work` directory contains the playbook's code.
@@ -76,7 +79,7 @@ docker run -it --rm \
 -v `pwd`:/work \
 -v $HOME/.ssh/id_rsa:/root/.ssh/id_rsa:ro \
 --entrypoint=/bin/sh \
-docker.io/devture/ansible:2.18.1-r0-0
+docker.io/devture/ansible:2.18.1-r0-2
 ```
 
 The above command tries to mount an SSH key (`$HOME/.ssh/id_rsa`) into the container (at `/root/.ssh/id_rsa`). If your SSH key is at a different path (not in `$HOME/.ssh/id_rsa`), adjust that part.