8.1 minor version update

Update content

1. The difficulty of 1-30 levels of simple mode was lowered again;

2. The property of city gate was adjusted by 24;

3. Added the first level of props when the plot performance;

4. The props given by the 2nd and 3rd levels were removed and collected in the menu gift bag instead;

5. Send General Li Guangfei as a gift on army day. Go to the gift bag to collect it.