[ci] use npm instead of pnpm

.woodpecker.yml

@@ -1,13 +1,13 @@
-pipeline:
+steps:
   build-and-push:
     image: plugins/docker
+    settings:
       registry: code.cozy.town
-    username: ${REGISTRY_USERNAME}
-    password: ${REGISTRY_TOKEN}
+      username:
+        from_secret: registry_username
+      password:
+        from_secret: registry_token
       repo: code.cozy.town/vrifox/hugoci
       tags:
         - latest
       cache_from: code.cozy.town/vrifox/hugoci:latest
-    secrets: 
-      - registry_username
-      - registry_token

Dockerfile

@@ -1,2 +1,4 @@
 FROM docker.io/alpine:latest
-RUN apk add --no-cache hugo git openssh rsync
+RUN apk add --no-cache hugo git openssh rsync npm
+RUN hugo version
+RUN npm --version