fix: narrow the eslint peer dep version range, avoiding npm 7 error (#5962)

Author: haoqunjiang

packages/@vue/cli-plugin-eslint/package.json

@@ -32,6 +32,6 @@
   },
   "peerDependencies": {
     "@vue/cli-service": "^3.0.0 || ^4.0.0-0",
-    "eslint": ">= 1.6.0"
+    "eslint": ">= 1.6.0 < 7.0.0"
   }
 }