Added arm64 architecture support in python-build for macOS (#1775)

* Update python-build with arm64 architecture

plugins/python-build/bin/python-build

@@ -995,7 +995,12 @@ build_package_activepython() {
 
 anaconda_architecture() {
   case "$(uname -s)" in
-  "Darwin" ) echo "MacOSX-x86_64" ;;
+  "Darwin" )
+    case "$(uname -m)" in
+    "arm64" ) echo "MacOSX-arm64" ;;
+    * ) echo "MacOSX-x86_64" ;;
+    esac
+    ;;
   "Linux" )
     case "$(uname -m)" in
     "armv7l" ) echo "Linux-armv7l" ;;