Bump MACOSX_DEPLOYMENT_TARGET to 10.15

Hopefully will fix nightly builds

Author: malfet

wheel/build_wheel.sh

@@ -124,7 +124,7 @@ popd
 
 export TH_BINARY_BUILD=1
 export INSTALL_TEST=0 # dont install test binaries into site-packages
-export MACOSX_DEPLOYMENT_TARGET=10.13
+export MACOSX_DEPLOYMENT_TARGET=10.15
 export CMAKE_PREFIX_PATH=${CONDA_PREFIX:-"$(dirname $(which conda))/../"}
 
 SETUPTOOLS_PINNED_VERSION="=46.0.0"