Add publishing

Set up publishing for multiple branches with different repos and registries.

package.json

@@ -8,26 +8,29 @@
     "dist",
     "src"
   ],
-  "publishing": [
-    {
+  "publishing": {
+    "master": {
+      "branch": "master",
       "repository": "https://code.modal.sh/TheoryOfNekomata/react-musical-keyboard.git",
       "publishConfig": {
         "registry": "https://js.pack.modal.sh"
       }
     },
-    {
+    "github": {
+      "branch": "github",
       "repository": "https://github.com/Temoto-kun/react-musical-keyboard",
       "publishConfig": {
         "registry": "https://npm.pkg.github.com"
       }
     },
-    {
+    "npm": {
+      "branch": "npm",
       "repository": "https://code.modal.sh/TheoryOfNekomata/react-musical-keyboard.git",
       "publishConfig": {
         "registry": "https://registry.npmjs.com"
       }
     }
-  ],
+  },
   "engines": {
     "node": ">=10"
   },