chore(deps): update plugins/docker docker tag to v20.18.6

.drone.yml

@@ -27,7 +27,7 @@ steps:
       - npm install -g better-npm-audit
       - better-npm-audit audit --production --level=moderate
   - name: docker-dry-run
-    image: plugins/docker:20.18.5@sha256:b8fc8f07a67b2c04905d41e3b9883595328c56843302ebc2b15ffe35bc7b0e76
+    image: plugins/docker:20.18.6@sha256:59c993e3c4e6c097a0e2d274419aac0d7d8e929773f0ba1af44078e54389834f
     settings:
       registry: git.wtf-eg.de
       repo: git.wtf-eg.de/kompetenzinventar/frontend
@@ -53,7 +53,7 @@ depends_on:
 
 steps:
   - name: docker-publish
-    image: plugins/docker:20.18.5@sha256:b8fc8f07a67b2c04905d41e3b9883595328c56843302ebc2b15ffe35bc7b0e76
+    image: plugins/docker:20.18.6@sha256:59c993e3c4e6c097a0e2d274419aac0d7d8e929773f0ba1af44078e54389834f
     settings:
       registry: git.wtf-eg.de
       repo: git.wtf-eg.de/kompetenzinventar/frontend
@@ -109,7 +109,7 @@ steps:
       - npm ci
       - npm run lint -- --no-fix
   - name: docker-publish
-    image: plugins/docker:20.18.5@sha256:b8fc8f07a67b2c04905d41e3b9883595328c56843302ebc2b15ffe35bc7b0e76
+    image: plugins/docker:20.18.6@sha256:59c993e3c4e6c097a0e2d274419aac0d7d8e929773f0ba1af44078e54389834f
     settings:
       registry: git.wtf-eg.de
       repo: git.wtf-eg.de/kompetenzinventar/frontend