Update GO_TOOLCHAIN string to Label and add toolchain param to one more action

[kotlaja]

What type of PR is this?
Other - Migration

What does this PR do? Why is it needed?
Because of the relative paths, we'll need GO_TOOLCHAIN as a Label, not a String. I saw this error by building @go_default_sdk//... from tests/bcr workspace.

Since it's not easy to see which actions are affected by these changes (sometimes it depends on projects which are using them), I'm updating these actions until I see green Bazel downstream projects. Before that I build the whole repo manually with the incompatible flag, but in some projects that is not enough (combinations of flags can affect this, executable/tools as variables from other projects, etc).

Which issues(s) does this PR fix?
Please check official documentation for Automatic Exec Groups for additional info.

[kotlaja]

@fmeum Can you please check this one too? :)

[fmeum]

@kotlaja Looks good to me, but there is a failure with Bazel 5.4.0. Could you take a look?

[kotlaja]

Ahh, Bazel 5.4.0 supports toolchain registration on a rule only as a String, not as a Label (see String parsing here).

I've used str func for this. PTAL. :)

[fmeum]

CI is still failing with a very obscure failure.

[kotlaja]

Seems that Bazel 5.4. has issues with str(Label(toolchain_string)) when registering toolchains on rules. The error is related to modified string of a toolchain which must be mapped 1-1 (changing it to label and then to a string changes that) or otherwise toolchain resolution doesn't find it as a registered one. I've separated it now into a Label and a String and updated toolchain parameters.

[kotlaja]

Thanks @fmeum for the quick responses and all the help! :)
By checking rules_go with multiple rules today, it seems that these changes are sufficient for the AEGs migration.

I know we had a release 4 days ago, but I'm interested when can we expect the next one?
I'll CC also @tyler-french here - Hi Tyler! :)