Add a universal build step for the library build

Author: tmthecoder

.github/workflows/dargon2_library-builder.yml

@@ -40,6 +40,10 @@ jobs:
         git clone https://github.com/P-H-C/phc-winner-argon2.git argon2_library
         cd argon2_library
         make
+        mv libargon2.1.dylib libargon2.1-x86_64.dylib
+        CFLAGS=--target=arm64-apple-macos11 make OPTTARGET=aarch64
+        mv libargon2.1.dylib libargon2.1-arm64.dylib
+        lipo -create libargon2.1-x86_64.dylib libargon2.1-arm64.dylib -output libargon2.1.dylib
     - name: copy and push library
       run: |
         cp argon2_library/libargon2.1.dylib lib/src/blobs/libargon2-darwin.dylib