bumping js-slang (#3108)

Co-authored-by: sayomaki <sayomayomaki@gmail.com>

Author: martin-henz

package.json

@@ -58,7 +58,7 @@
     "i18next-browser-languagedetector": "^8.0.0",
     "java-slang": "^1.0.13",
     "js-cookie": "^3.0.5",
-    "js-slang": "^1.0.80",
+    "js-slang": "^1.0.81",
     "js-yaml": "^4.1.0",
     "konva": "^9.2.0",
     "language-directory": "https://github.com/source-academy/language-directory.git",