fix: loadOptions test regex

[Nedgeva]

Motivation

Fixes #727

Summary

Changes test regex in loadOptions to match node_modules path on Win machines, not only nix.

Test plan

1. create sample project with react, linaria and webpack
2. make dummy react component wrapped into react's memo
3. wrap abovementioned react component into linaria's styled
4. run build in different envs (e.g. linux, macos, windows)
5. build should finish with success

[callstack-bot]

Hey @Nedgeva, thank you for your pull request 🤗.
The coverage report for this branch can be viewed here.

[Anber]

Thank you @Nedgeva!