Add fuse dependency to moby/buildkit image

Currently moby/buildkit image misses fuse dependency (fusermount) so currently
stargz support doesn't work on that image. This commit fixes this issue.

Signed-off-by: ktock <ktokunaga.mail@gmail.com>
Signed-off-by: fahed dorgaa <fahed.dorgaa@gmail.com>

Dockerfile

@@ -129,6 +129,7 @@ FROM scratch AS release
 COPY --from=releaser /out/ /
 
 FROM tonistiigi/git@sha256:393483e1cef35f09e1a8fe0a0bd93a78b1b6ecec5b5afa5fa5d600fa3ab1fdd8 AS buildkit-export
+RUN apk add --no-cache fuse3 && ln -s fusermount3 /usr/bin/fusermount
 COPY examples/buildctl-daemonless/buildctl-daemonless.sh /usr/bin/
 VOLUME /var/lib/buildkit