Update docker.elastic.co/ci-agent-images/drivah Docker tag to v0.26.0 (…

…#274)

This PR contains the following updates:

| Package | Update | Change |
|---|---|---|
| docker.elastic.co/ci-agent-images/drivah | minor | `0.25.3` ->
`0.26.0` |

---

Co-authored-by: elastic-renovate-prod[bot] <174716857+elastic-renovate-prod[bot]@users.noreply.github.com>

.buildkite/pipeline.yml

@@ -25,7 +25,7 @@ steps:
       - .buildkite/registry-login.sh
       - drivah build --push .
     agents:
-      image: "docker.elastic.co/ci-agent-images/drivah:0.25.3"
+      image: "docker.elastic.co/ci-agent-images/drivah:0.26.0"
       cpu: "4"
       memory: "4G"
       ephemeralStorage: "20G"