chore(deps): update qemux/qemu-docker docker tag to v5.15 (#590)

Co-authored-by: renovate[bot] <29139614+renovate[bot]@users.noreply.github.com>

Dockerfile

@@ -1,5 +1,5 @@
 FROM scratch
-COPY --from=qemux/qemu-docker:5.13 / /
+COPY --from=qemux/qemu-docker:5.15 / /
 
 ARG VERSION_ARG="0.0"
 ARG DEBCONF_NOWARNINGS="yes"