integration: download busybox-w32 from GitHub Release

Signed-off-by: CrazyMax <crazy-max@users.noreply.github.com>
(cherry picked from commit 4f1d1422deb1a8cf43a3b39c7eb65581aedb6013)
Signed-off-by: Sebastiaan van Stijn <github@gone.nl>

contrib/busybox/Dockerfile

@@ -19,7 +19,7 @@ FROM ${WINDOWS_BASE_IMAGE}:${WINDOWS_BASE_IMAGE_TAG}
 RUN mkdir C:\tmp && mkdir C:\bin
 ARG BUSYBOX_VERSION
 ARG BUSYBOX_SHA256SUM
-ADD https://frippery.org/files/busybox/busybox-w32-${BUSYBOX_VERSION}.exe /bin/busybox.exe
+ADD https://github.com/moby/busybox/releases/download/${BUSYBOX_VERSION}/busybox-w32-${BUSYBOX_VERSION}.exe /bin/busybox.exe
 RUN powershell \
     if ((Get-FileHash -Path /bin/busybox.exe -Algorithm SHA256).Hash -ne $Env:BUSYBOX_SHA256SUM) { \
         Throw \"Checksum validation failed\" \