chore(deps): update docker docker tag to v26 (#29)

This PR contains the following updates:

| Package | Update | Change |
|---|---|---|
| docker | major | `25.0.5` -> `26.0.0` |

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### Configuration

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🚦 **Automerge**: Disabled by config. Please merge this manually once you are satisfied.

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Reviewed-on: #29
Co-authored-by: Renovate Bot <renovate@mgrote.net>
Co-committed-by: Renovate Bot <renovate@mgrote.net>

.woodpecker/build.yml

@@ -30,7 +30,7 @@ steps:
         echo "DATE=$DATE" >> .variables
 
   build_and_push: # damit dieser Step laufen kann muss das Repo in der Woodpecker-GUI "privilegiert" sein
-    image: "docker:25.0.5"
+    image: "docker:26.0.0"
     volumes:
       - /var/run/docker.sock:/var/run/docker.sock
     commands: