fix: switch back to plugins/docker for image builds

The woodpeckerci/plugin-docker-buildx plugin started dockerd correctly
(privileged mode works) but failed DockerHub authentication. Switch back
to plugins/docker which is proven working in realestate-crawler pipeline.

.woodpecker.yml

@@ -30,9 +30,11 @@ steps:
         cp -r .pip-cache /woodpecker/pip-cache 2>/dev/null || true
 
   - name: build-service-image
-    image: woodpeckerci/plugin-docker-buildx
+    image: plugins/docker
     depends_on:
       - test
+    environment:
+      DOCKER_BUILDKIT: 1
     settings:
       username: viktorbarzin
       password:
@@ -44,14 +46,16 @@ steps:
         - EXTRAS=api,news,sentiment,trading,backtester
         - SERVICE_MODULE=api_gateway
       cache_from:
-        - type=registry,ref=viktorbarzin/trading-bot-service:latest
+        - viktorbarzin/trading-bot-service:latest
       tags:
         - "build-${CI_PIPELINE_NUMBER}"
 
   - name: build-dashboard-image
-    image: woodpeckerci/plugin-docker-buildx
+    image: plugins/docker
     depends_on:
       - test
+    environment:
+      DOCKER_BUILDKIT: 1
     settings:
       username: viktorbarzin
       password:
@@ -62,7 +66,7 @@ steps:
       build_args:
         - NGINX_CONF=docker/nginx-k8s.conf
       cache_from:
-        - type=registry,ref=viktorbarzin/trading-bot-dashboard:latest
+        - viktorbarzin/trading-bot-dashboard:latest
       tags:
         - "build-${CI_PIPELINE_NUMBER}"