fix docker multiplatform

Author: lastarc

Dockerfile

@@ -1,12 +1,13 @@
 FROM alpine:latest
 
 ARG PB_VERSION=0.22.14
+ARG TARGETARCH
 
 RUN apk add --no-cache \
     unzip \
     ca-certificates
 
-ADD https://github.com/pocketbase/pocketbase/releases/download/v${PB_VERSION}/pocketbase_${PB_VERSION}_linux_amd64.zip /tmp/pb.zip
+ADD https://github.com/pocketbase/pocketbase/releases/download/v${PB_VERSION}/pocketbase_${PB_VERSION}_linux_${TARGETARCH}.zip /tmp/pb.zip
 RUN unzip /tmp/pb.zip -d /pb/
 
 COPY ./pb_migrations /pb/pb_migrations