sextractor: update openblas's include dir

[cho-m]

• Have you followed the guidelines for contributing?
• Have you ensured that your commits follow the commit style guide?
• Have you checked that there aren't other open pull requests for the same formula update/change?
• Have you built your formula locally with HOMEBREW_NO_INSTALL_FROM_API=1 brew install --build-from-source <formula>, where <formula> is the name of the formula you're submitting?
• Is your test running fine brew test <formula>, where <formula> is the name of the formula you're submitting?
• Does your build pass brew audit --strict <formula> (after doing HOMEBREW_NO_INSTALL_FROM_API=1 brew install --build-from-source <formula>)? If this is a new formula, does it pass brew audit --new <formula>?

---

Split from #219339 as shouldn't need new bottle.

Seems like CMake defaults to subdirectory. Some distros do use Make and manually set subdirectory like Fedora (https://src.fedoraproject.org/rpms/openblas/blob/rawhide/f/openblas.spec#_433) so to move to subdirectory if we want.