refactor(datasource): getPkgReleases -> getReleases (#5867)

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

lib/datasource/cdnjs/index.spec.ts

lib/datasource/cdnjs/index.ts

lib/datasource/common.ts

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

lib/datasource/crate/index.spec.ts

lib/datasource/crate/index.ts

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

lib/datasource/dart/index.spec.ts

lib/datasource/dart/index.ts

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

lib/datasource/docker/index.spec.ts

lib/datasource/docker/index.ts

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

lib/datasource/galaxy/index.spec.ts

lib/datasource/galaxy/index.ts

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

lib/datasource/git-refs/index.ts

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

lib/datasource/git-submodules/index.ts