Specify max version of npm

Test runners have to run in Node 12+ and npm 9+ does not have backward compatibility in package-lock.

Author: Nixinova

package-lock.json

@@ -23,7 +23,8 @@
         "dist/"
     ],
     "engines": {
-        "node": ">=12"
+        "node": ">=12",
+        "npm": "<9"
     },
     "repository": {
         "type": "git",