release: Bump version number to 12.4.0 (#9594)

package-lock.json

@@ -1471,7 +1471,7 @@
       }
     },
     "packages/blockly": {
-      "version": "12.3.1",
+      "version": "12.4.0",
       "hasInstallScript": true,
       "license": "Apache-2.0",
       "dependencies": {

packages/blockly/package.json

@@ -1,6 +1,6 @@
 {
   "name": "blockly",
-  "version": "12.3.1",
+  "version": "12.4.0",
   "description": "Blockly is a library for building visual programming editors.",
   "keywords": [
     "blockly"