fix: revert changes to dockerfile

Signed-off-by: Hung-Han (Henry) Chen <[email protected]>

Dockerfile

@@ -2,19 +2,17 @@
 
 # Keycloak base image version, set with --build-arg="KEYCLOAK_VERSION=..."
 ARG KEYCLOAK_VERSION
-ARG TARGETPLATFORM
 
 # See "Installing additional RPM packages" https://www.keycloak.org/server/containers
-FROM --platform=$TARGETPLATFORM registry.access.redhat.com/ubi9 AS ubi-micro-build
-
+FROM registry.access.redhat.com/ubi9 AS ubi-micro-build
 ARG DEV_DEPENDENCIES="tar gzip util-linux"
 RUN mkdir -p /mnt/rootfs
 RUN dnf -y update
 RUN dnf install --installroot /mnt/rootfs ${DEV_DEPENDENCIES} --releasever 9 --setopt install_weak_deps=false --nodocs -y && \
     dnf --installroot /mnt/rootfs clean all && \
     rpm --root /mnt/rootfs -e --nodeps setup
 
-FROM --platform=$TARGETPLATFORM quay.io/keycloak/keycloak:${KEYCLOAK_VERSION}
+FROM quay.io/keycloak/keycloak:${KEYCLOAK_VERSION}
 COPY --from=ubi-micro-build /mnt/rootfs /
 
 ENTRYPOINT ["/opt/keycloak/bin/kc.sh"]