[feature] Update generic builder type

[laurentsimon]

The Go builder type has:

"buildType": "https://github.com/slsa-framework/slsa-github-generator/go@v1",

the generic generator ahs:

"buildType": "https://github.com/slsa-framework/slsa-github-generator@v1",

I'm not sure this is consistent. Should the latter be https://github.com/slsa-framework/slsa-github-generator/generic@v1?

Or maybe we should keep https://github.com/slsa-framework/slsa-github-generator@v1 for all of them, since the builder name is available anyway?

/cc @ianlewis

[ianlewis]

Yeah, I think https://github.com/slsa-framework/slsa-github-generator/generic@v1 is more consistent since it fits into a https://github.com/slsa-framework/slsa-github-generator/<builder-name>@v1 pattern.