refactor: Import index for datasource tests (part 2) (#6546)

lib/datasource/docker/index.spec.ts

lib/datasource/git-refs/index.spec.ts

lib/datasource/git-submodules/index.spec.ts

lib/datasource/git-tags/index.spec.ts

...tasource/github-releases/__snapshots__/index.spec.ts.snap

lib/datasource/github-releases/index.spec.ts

lib/datasource/github-tags/index.spec.ts

lib/datasource/gitlab-tags/__snapshots__/index.spec.ts.snap

lib/datasource/gitlab-tags/index.spec.ts

lib/datasource/go/index.spec.ts

...atasource/gradle-version/__snapshots__/index.spec.ts.snap

lib/datasource/gradle-version/index.spec.ts

lib/datasource/maven/index.spec.ts

lib/datasource/npm/__snapshots__/index.spec.ts.snap

lib/datasource/npm/index.spec.ts

lib/datasource/nuget/__snapshots__/index.spec.ts.snap

lib/datasource/nuget/index.spec.ts

lib/datasource/orb/__snapshots__/index.spec.ts.snap

lib/datasource/orb/index.spec.ts

lib/datasource/packagist/__snapshots__/index.spec.ts.snap