Disable provenance feature on docker build for unsupported platforms

[kurochan]

What this PR does / why we need it:

Explicitly set provenance=false on docker build. Because of PipeCD supports CloudRun and related to issue docker/buildx#1533 .

However, the provenance is a part of security feature, I am wondering whether it should be uniformly disabled.

Which issue(s) this PR fixes:

Related:

Does this PR introduce a user-facing change?:

NONE

[knanao]

All images used by Cloud Run are pushed to GCR.
Hence how about just fixing the image used by Cloud Run?

[knanao]

Thank you for sharing the issue.

From this comment, I've actually checked whether Cloud Run has already supported multi-platform built, and it works as expected in both GCR and GAR.
docker/buildx#1533 (comment)

But currently, the actions' version which we're using is not affected by this.
Hence let us update the necessary config when using this feature.
https://github.com/docker/build-push-action#:~:text=Subdirectory%20for%20Git,at%20the%20moment.

That's why let me close this temporarily.