use docker build path context

[minghinmatthewlam]

Why this should be merged

Release action for publish docker image is failing, this hopes to address and fix.

How this works

for build-push-action docs, specifies we use git context without the checkout action, or if we use checkout action we should pass in path context. So this PR is adding the path context since we do use checkout action.

How this was tested

n/a

How is this documented

n/a

[michaelkaplan13]

Given that we don't modify any files after the checkout step, it seems like the recommended use here would be to not have the separate checkout step at all, and just use the default git context. I could be missing some context though.

[minghinmatthewlam]

in the build-push-actions docs https://github.com/docker/build-push-action, by default it doesn't use the checkout action, and wouldn't need the additionial context: . , but think this is easier to read and more inline with the other workflows that use the checkout option. Discussed offline, will leave in this format.