Specify `docker as container-runtime` for setup-minikube action

minikube v1.39.0 changed the default container runtime to `containerd`,
(see: https://github.com/kubernetes/minikube/releases/tag/v1.39.0 ),
which currently doesn't work with the `none` driver:
https://github.com/kubernetes/minikube/issues/21985

Fix the following error on CI integration workflows:

```
* minikube v1.39.0 on Ubuntu 24.04
* Using the none driver based on user configuration
! Using the 'containerd' runtime with the 'none' driver is an untested configuration!
* Starting "minikube" primary control-plane node in "minikube" cluster
* Running on localhost (CPUs=4, Memory=15988MB, Disk=147718MB) ...
* OS release is Ubuntu 24.04.4 LTS

X Exiting due to RUNTIME_ENABLE: Failed to start container runtime: Temporary Error: sudo /usr/local/bin/crictl version: exit status 1
stdout:

stderr:
time="2026-09-02T22:08:14Z" level=fatal msg="validate service connection: validate CRI v1 runtime API for endpoint \"unix:///run/containerd/containerd.sock\": rpc error: code = Unimplemented desc = unknown service runtime.v1.RuntimeService"
```

.github/workflows/integration.yaml

@@ -53,6 +53,7 @@ jobs:
         uses: medyagh/setup-minikube@latest
         with:
           driver: none
+          container-runtime: docker
           kubernetes-version: '1.28.0'
       - name: Check pods
         run: kubectl get pods -A