chore: auto update READMEs

Author: github-actions[bot]

Solvesql/README.md

@@ -45,6 +45,8 @@
 | 2 | [할부는 몇 개월로 해드릴까요](https://solvesql.com/problems/installment-month/) | Aggregate | [Solution](https://github.com/SubAkBa/Algorithm_Solution/blob/master/Solvesql/Solutions/installment-month.sql) |  |
 | 3 | [지역별 주문의 특징](https://solvesql.com/problems/characteristics-of-orders/) | CASE/IF | [Solution](https://github.com/SubAkBa/Algorithm_Solution/blob/master/Solvesql/Solutions/characteristics-of-orders.sql) |  |
 | 4 | [(Unknown Title)](https://solvesql.com/problems/estimated-delivery-date/) |  | [Solution](https://github.com/SubAkBa/Algorithm_Solution/blob/master/Solvesql/Solutions/estimated-delivery-date.sql) |  |
+| 5 | [작품이 없는 작가 찾기](https://solvesql.com/problems/artists-without-artworks/) | JOIN/UNION | [Solution](https://github.com/SubAkBa/Algorithm_Solution/blob/master/Solvesql/Solutions/artists-without-artworks.sql) |  |
+| 6 | [멘토링 짝꿍 리스트](https://solvesql.com/problems/mentor-mentee-list/) | JOIN/UNION | [Solution](https://github.com/SubAkBa/Algorithm_Solution/blob/master/Solvesql/Solutions/mentor-mentee-list.sql) |  |
 
 </details>