Add publishing

Setup publishing for multiple repos and registries.

README.md

@@ -8,7 +8,7 @@ This component is currently available in:
 
 * [Modal.sh JavaScript Package Registry](https://js.pack.modal.sh)
 * [npm](https://npmjs.com)
-* [GitHub Package Registry](https://github.com/Temoto-kun/react-musical-keyboard/packages) for the [Github mirror](https://github.com/Temoto-kun/react-musical-keyboard)
+* [GitHub Package Registry](https://npm.pkg.github.com)
 
 Once set up, install the package from the registry:
 

package.json

@@ -8,6 +8,26 @@
     "dist",
     "src"
   ],
+  "publishing": [
+    {
+      "repository": "https://code.modal.sh/TheoryOfNekomata/react-musical-keyboard.git",
+      "publishConfig": {
+        "registry": "https://js.pack.modal.sh"
+      }
+    },
+    {
+      "repository": "https://github.com/Temoto-kun/react-musical-keyboard",
+      "publishConfig": {
+        "registry": "https://npm.pkg.github.com"
+      }
+    },
+    {
+      "repository": "https://code.modal.sh/TheoryOfNekomata/react-musical-keyboard.git",
+      "publishConfig": {
+        "registry": "https://registry.npmjs.com"
+      }
+    }
+  ],
   "engines": {
     "node": ">=10"
   },