Re-build image to use latest kaniko version

[xoen]

Hello,

First of all thanks for working on this Concourse resource :)

I've noticed that the Docker image is quite old (29 Sep). Would be possible to rebuild/push the docker image?

I've seen they've fixed a caching problem it was effecting us (but this was a regression so maybe this docker image is not affected), another other caching improvement and possibly others.

It would be worth testing if latest version of kaniko still works and if it does upgrade so this is not too much behind.

PS: It would be great to tag docker images with semantic versions. I see that kaniko itself has versions/releases, but currently Dockerfile go-get the latest version so this may be a bit more involved if you'll need to vendor the dependencies, etc...