Merge pull request numpy#20342 from seberg/ci-updated-macos

CI: Bump azure MacOS version to macOS-1015

Author: rgommers

azure-pipelines.yml

@@ -109,7 +109,7 @@ stages:
       # the docs even though i.e., numba uses another in their
       # azure config for mac os -- Microsoft has indicated
       # they will patch this issue
-      vmImage: 'macOS-10.14'
+      vmImage: 'macOS-1015'
     strategy:
       maxParallel: 3
       matrix: