Only build universal binaries in CI for releases

This will reduce build time during development.

CMakeLists.txt

@@ -20,6 +20,14 @@ project(${PROJECT_NAME} VERSION ${CURRENT_VERSION})
 # By default we don't want Xcode schemes to be made for modules, etc
 set(CMAKE_XCODE_GENERATE_SCHEME OFF)
 
+
+# Building universal binaries on macOS increases build time
+# This is set on CI but not during local dev
+if ((DEFINED ENV{CI}) AND (CMAKE_BUILD_TYPE STREQUAL "Release"))
+    message("Building for Apple Silicon and x86_64")
+    set(CMAKE_OSX_ARCHITECTURES arm64 x86_64)
+endif ()
+
 # Enable to build universal binaries on macOS, increasing build time
 # This only affects local builds, GitHub actions always builds Universals
 # set(CMAKE_OSX_ARCHITECTURES arm64 x86_64)