Move the prettier package to peer dependencies

Author: titouanmathis

package.json

@@ -41,7 +41,9 @@
     "chalk": "^4.1.0",
     "jest-diff": "^26.6.2",
     "js-yaml": "^3.14.0",
-    "prettier-linter-helpers": "^1.0.0",
-    "prettier": "^2.2.0"
+    "prettier-linter-helpers": "^1.0.0"
+  },
+  "peerDependencies": {
+    "prettier": ">=2"
   }
 }