update to mobx-react v6, remove mobx-react-devtools as it is not compatible with v6

package.json

@@ -23,17 +23,16 @@
   },
   "homepage": "http://mobxjs.github.com/mobx",
   "devDependencies": {
-    "@types/react-dom": "^16.0.9",
+    "@types/react-dom": "^16.9.2",
     "awesome-typescript-loader": "^5.2.1",
-    "typescript": "^3.1.3",
-    "webpack": "^4.22.0",
-    "webpack-dev-server": "^3.1.10"
+    "typescript": "^3.6.4",
+    "webpack": "^4.41.2",
+    "webpack-dev-server": "^3.8.2"
   },
   "dependencies": {
-    "mobx": "^5.5.2",
-    "mobx-react": "^5.3.5",
-    "mobx-react-devtools": "^6.0.3",
-    "react": "^16.5.2",
-    "react-dom": "^16.5.2"
+    "mobx": "^5.14.2",
+    "mobx-react": "^6.1.4",
+    "react": "^16.10.2",
+    "react-dom": "^16.10.2"
   }
 }

src/index.tsx

@@ -2,7 +2,6 @@ import * as React from 'react';
 import * as ReactDOM from 'react-dom';
 import {observable} from 'mobx';
 import {observer} from 'mobx-react';
-import DevTools from 'mobx-react-devtools';
 
 class AppState {
     @observable timer = 0;
@@ -26,7 +25,6 @@ class TimerView extends React.Component<{appState: AppState}, {}> {
                 <button onClick={this.onReset}>
                     Seconds passed: {this.props.appState.timer}
                 </button>
-                <DevTools />
             </div>
         );
      }