Add @glimmer/validator as peerDependency

Author: ctjhoa

packages/ember-render-modifiers/package.json

@@ -49,7 +49,13 @@
     "rollup": "^2.71.1"
   },
   "peerDependencies": {
-    "ember-source": "^3.8 || ^4.0"
+    "ember-source": "^3.8 || ^4.0",
+    "@glimmer/validator": "*"
+  },
+  "peerDependenciesMeta": {
+    "@glimmer/validator": {
+      "optional": true
+    }
   },
   "engines": {
     "node": "12.* || 14.* || >= 16"