tools: Update to the latest linuxkit/alpine

with the exception of grub. It does not compile
with the latest version, see: https://github.com/linuxkit/linuxkit/issues/3494

Signed-off-by: Rolf Neugebauer <rn@rneugeba.io>

tools/go-compile/Dockerfile

@@ -1,4 +1,4 @@
-FROM linuxkit/alpine:86cd4f51b49fb9a078b50201d892a3c7973d48ec AS mirror
+FROM linuxkit/alpine:bc528cf9d4065d2e09aa44ff76909b94cfe8d867 AS mirror
 
 RUN mkdir -p /out/etc/apk && cp -r /etc/apk/* /out/etc/apk/
 RUN apk add --no-cache --initdb -p /out \

tools/mkimage-iso-bios/Dockerfile

@@ -1,4 +1,4 @@
-FROM linuxkit/alpine:86cd4f51b49fb9a078b50201d892a3c7973d48ec as mirror
+FROM linuxkit/alpine:bc528cf9d4065d2e09aa44ff76909b94cfe8d867 as mirror
 RUN mkdir -p /out/etc/apk && cp -r /etc/apk/* /out/etc/apk/
 RUN apk add --no-cache --initdb -p /out \
     alpine-baselayout \

tools/mkimage-iso-efi/Dockerfile

@@ -1,6 +1,6 @@
 FROM linuxkit/grub:a0e2211d39c3c71613f902b3e29746badee3295e AS grub
 
-FROM linuxkit/alpine:86cd4f51b49fb9a078b50201d892a3c7973d48ec AS mirror
+FROM linuxkit/alpine:bc528cf9d4065d2e09aa44ff76909b94cfe8d867 AS mirror
 RUN mkdir -p /out/etc/apk && cp -r /etc/apk/* /out/etc/apk/
 RUN apk add --no-cache --initdb -p /out \
   alpine-baselayout \

tools/mkimage-iso/Dockerfile

@@ -1,4 +1,4 @@
-FROM linuxkit/alpine:86cd4f51b49fb9a078b50201d892a3c7973d48ec AS mirror
+FROM linuxkit/alpine:bc528cf9d4065d2e09aa44ff76909b94cfe8d867 AS mirror
 RUN mkdir -p /out/etc/apk && cp -r /etc/apk/* /out/etc/apk/
 RUN apk add --no-cache --initdb -p /out \
     alpine-baselayout \

tools/mkimage-qcow2-efi/Dockerfile

@@ -1,6 +1,6 @@
 FROM linuxkit/grub:a0e2211d39c3c71613f902b3e29746badee3295e AS grub
 
-FROM linuxkit/alpine:86cd4f51b49fb9a078b50201d892a3c7973d48ec AS mirror
+FROM linuxkit/alpine:bc528cf9d4065d2e09aa44ff76909b94cfe8d867 AS mirror
 RUN mkdir -p /out/etc/apk && cp -r /etc/apk/* /out/etc/apk/
 RUN apk add --no-cache --initdb -p /out \
   alpine-baselayout \

tools/mkimage-raw-bios/Dockerfile

@@ -1,4 +1,4 @@
-FROM linuxkit/alpine:86cd4f51b49fb9a078b50201d892a3c7973d48ec AS mirror
+FROM linuxkit/alpine:bc528cf9d4065d2e09aa44ff76909b94cfe8d867 AS mirror
 RUN mkdir -p /out/etc/apk && cp -r /etc/apk/* /out/etc/apk/
 RUN apk add --no-cache --initdb -p /out \
     alpine-baselayout \

tools/mkimage-raw-efi/Dockerfile

@@ -1,6 +1,6 @@
 FROM linuxkit/grub:a0e2211d39c3c71613f902b3e29746badee3295e AS grub
 
-FROM linuxkit/alpine:86cd4f51b49fb9a078b50201d892a3c7973d48ec AS mirror
+FROM linuxkit/alpine:bc528cf9d4065d2e09aa44ff76909b94cfe8d867 AS mirror
 RUN mkdir -p /out/etc/apk && cp -r /etc/apk/* /out/etc/apk/
 RUN apk add --no-cache --initdb -p /out \
   alpine-baselayout \

tools/mkimage-rpi3/Dockerfile

@@ -1,4 +1,4 @@
-FROM linuxkit/alpine:86cd4f51b49fb9a078b50201d892a3c7973d48ec as build
+FROM linuxkit/alpine:bc528cf9d4065d2e09aa44ff76909b94cfe8d867 as build
 RUN apk add \
     bc \
     bison \

tools/mkimage-squashfs/Dockerfile

@@ -1,4 +1,4 @@
-FROM linuxkit/alpine:86cd4f51b49fb9a078b50201d892a3c7973d48ec AS mirror
+FROM linuxkit/alpine:bc528cf9d4065d2e09aa44ff76909b94cfe8d867 AS mirror
 RUN mkdir -p /out/etc/apk && cp -r /etc/apk/* /out/etc/apk/
 RUN apk add --no-cache --initdb -p /out \
   alpine-baselayout \