set arch flags for macos

Author: cvanelteren

.github/workflows/build.yml

@@ -58,6 +58,7 @@ jobs:
               python -c "import utils; utils.GeosLibrary('${GEOS_VERSION}').build('${GEOS_DIR}', njobs=2)"
           - os: macos-latest
             before_all: >-
+              ARCHFLAGS="-arch x86_64 -arch arm64"
               echo "Starting BEFORE_ALL script" &&
               echo "GEOS_DIR set to: ${GEOS_DIR}" &&
               cd "{package}" &&