fix(android): webview crash with incognito in Android Lollipop (#799)

android/src/main/java/com/reactnativecommunity/webview/RNCWebViewManager.java

   @ReactProp(name = "incognito")
   public void setIncognito(WebView view, boolean enabled) {
     // Remove all previous cookies
-    CookieManager.getInstance().removeAllCookies(null);
+    if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP) {
+      CookieManager.getInstance().removeAllCookies(null);
+    } else {
+      CookieManager.getInstance().removeAllCookie();
+    }
 
     // Disable caching
     view.getSettings().setCacheMode(WebSettings.LOAD_NO_CACHE);