build: docker typo fix

Author: reddec

Dockerfile

@@ -6,5 +6,5 @@ ENV API_KV_BIND=":8080" \
     API_KV_DIR="/data" \
     API_KV_TOKEN="changeme"
 ENTRYPOINT ["/api-kv"]
-RUN ["serve"]
+CMD ["serve"]
 ADD api-kv /