Updated Compile and install on macOS using macports (markdown)

Compile-and-install-on-macOS-using-macports.md

@@ -19,8 +19,9 @@ Install dependencies through port:
 
 Install create-dmg:
 
-    sudo port -N install npm7
-    sudo npm install --global create-dmg
+    wget https://raw.githubusercontent.com/create-dmg/create-dmg/master/create-dmg
+    chmod u+x create-dmg
+    sudo mv create-dmg /opt/local/bin/
 
 Set environment variables: