Require at least macOS 10.15

Author: Schwaggot

.github/workflows/wheels.yml

@@ -40,6 +40,7 @@ jobs:
           CIBW_ARCHS_LINUX: x86_64 aarch64
           CIBW_ARCHS_MACOS: x86_64 arm64
           CIBW_ARCHS_WINDOWS: AMD64
+          CIBW_ENVIRONMENT_MACOS: "MACOSX_DEPLOYMENT_TARGET=10.15"
           CIBW_TEST_REQUIRES: pytest
           CIBW_TEST_COMMAND: pytest {project}/tests -v
           CIBW_BUILD_VERBOSITY: 1