feat: upgrade flowchart.js to version 1.15.0

Signed-off-by: Max Wu <jackymaxj@gmail.com>

Author: jackycute

package-lock.json

@@ -130,7 +130,7 @@
     "expose-loader": "~0.7.5",
     "file-loader": "~2.0.0",
     "file-saver": "~2.0.2",
-    "flowchart.js": "~1.12.2",
+    "flowchart.js": "~1.15.0",
     "fork-awesome": "~1.1.7",
     "gist-embed": "~2.6.0",
     "graceful-fs": "~4.2.1",