chore(datasource): move test files to lib (#5426)

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

lib/datasource/__snapshots__/metadata.spec.ts.snap

lib/datasource/cargo/__fixtures__/amethyst

lib/datasource/cargo/__fixtures__/invalid_crate_data

lib/datasource/cargo/__fixtures__/libc

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

lib/datasource/cargo/index.spec.ts

lib/datasource/cdnjs/__fixtures__/bulma.json

lib/datasource/cdnjs/__fixtures__/d3-force.json

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

lib/datasource/cdnjs/index.spec.ts

lib/datasource/dart/__fixtures__/shared_preferences.json

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

lib/datasource/dart/index.spec.ts

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

lib/datasource/docker/index.spec.ts

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

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

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

lib/datasource/github/index.spec.ts