Fix binfmt for docker.

020_docker-fmts.sh

@@ -0,0 +1,21 @@
+#!/usr/bin/env bash
+
+# https://docs.docker.com/build/building/multi-platform/#qemu-without-docker-desktop
+
+echo "Before:"
+docker buildx ls
+
+apt-get install -y binfmt_misc
+
+docker run --privileged --rm tonistiigi/binfmt --install all
+
+echo "After:"
+docker buildx ls
+
+# expect:
+# docker buildx ls
+# NAME/NODE     DRIVER/ENDPOINT   STATUS    BUILDKIT   PLATFORMS
+# default*      docker
+#  \_ default    \_ default       running   v0.13.1    linux/amd64, linux/386,
+#  linux/arm64, linux/riscv64, linux/ppc64, linux/ppc64le, linux/s390x, linux/mips64le,
+#  linux/mips64, linux/arm/v7, linux/arm/v6