move preact to a peer dep

Author: developit

package.json

@@ -65,13 +65,14 @@
     "eslint-plugin-react": "^7.4.0",
     "mocha": "^4.0.1",
     "npm-run-all": "^4.1.1",
+    "preact": "^8.2.6",
     "rollup": "^0.36.3",
     "rollup-plugin-babel": "^2.6.1",
     "rollup-plugin-es3": "^1.0.3",
     "rollup-plugin-post-replace": "^1.0.0",
     "uglify-js": "^2.7.4"
   },
-  "dependencies": {
-    "preact": "^8.2.6"
+  "peerDependencies": {
+    "preact": "*"
   }
 }