fix: remove multiple build

Signed-off-by: Bo-Yi Wu <appleboy.tw@gmail.com>

Dockerfile

@@ -1,4 +1,9 @@
-FROM plugins/base:amd64 AS builder
+FROM plugins/base:amd64
+
+LABEL maintainer="Bo-Yi Wu <appleboy.tw@gmail.com>" \
+  org.label-schema.name="Drone Packer" \
+  org.label-schema.vendor="Bo-Yi Wu" \
+  org.label-schema.schema-version="1.0"
 
 RUN apk add --no-cache ca-certificates \
   wget && \
@@ -9,15 +14,5 @@ RUN wget -q https://releases.hashicorp.com/packer/${PACKER_VERSION}/packer_${PAC
   unzip packer.zip -d /bin && \
   rm -f packer.zip
 
-FROM plugins/base:multiarch
-
-LABEL maintainer="Bo-Yi Wu <appleboy.tw@gmail.com>" \
-  org.label-schema.name="Drone Packer" \
-  org.label-schema.vendor="Bo-Yi Wu" \
-  org.label-schema.schema-version="1.0"
-
-ENV PACKER_LOG 0
-
-COPY --from=builder bin/packer /bin/
 ADD release/linux/amd64/drone-packer /bin/
 ENTRYPOINT ["/bin/drone-packer"]