Reinstate libcxx version that matches compiler

[h-vetinari]

We've finally caught back up after conda-forge/libcxx-feedstock#155 got merged. 🙃

C.f. list in #131 (resp. #113 before #128)

[conda-forge-webservices]

Hi! This is the friendly automated conda-forge-linting service.

I just wanted to let you know that I linted all conda-recipes in your PR (recipe) and found it was in an excellent condition.

[h-vetinari]

Waiting for conda-forge/libcxx-feedstock#160

[h-vetinari]

Draft at least until we fix conda-forge/libcxx-feedstock#162

[conda-forge-webservices]

Hi! This is the friendly automated conda-forge-linting service.

I just wanted to let you know that I linted all conda-recipes in your PR (recipe/meta.yaml) and found it was in an excellent condition.

[h-vetinari]

@conda-forge/clang-compiler-activation, with this PR we're finally ready to go back to the way things worked before the macOS 10.13 bump caused things to diverge for a while. PTAL :)

[h-vetinari]

Gentle ping @conda-forge/clang-compiler-activation :)

[isuruf]

Let's keep libcxx_major jinja variable and set it to version? Reduces churn now and in the future too.

[github-actions]

Hi! This is the friendly conda-forge automerge bot!

I considered the following status checks when analyzing this PR:

• linter: passed
• azure: passed

Thus the PR was passing and merged! Have a great day!