chore(jest): add eslint jest checks (#5986)

.eslintrc.js

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

lib/config/index.spec.ts

lib/config/migration.spec.ts

lib/config/validation.spec.ts

lib/datasource/cdnjs/index.spec.ts

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

lib/datasource/crate/index.spec.ts

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

lib/datasource/go/index.spec.ts

lib/datasource/hex/index.spec.ts

lib/datasource/npm/index.spec.ts

lib/datasource/npm/index.ts

lib/datasource/npm/npmrc.spec.ts

lib/datasource/nuget/index.spec.ts

lib/datasource/pod/index.spec.ts

lib/datasource/sbt-package/index.spec.ts