feat(internal): use runtime cache for buffering global cache requests (#6202)

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

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

lib/datasource/helm/index.spec.ts

lib/datasource/helm/index.ts

lib/datasource/nuget/index.spec.ts

lib/datasource/orb/index.spec.ts

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

lib/util/cache/global.ts

lib/workers/pr/changelog/index.spec.ts