Update README.md

Author: hwangJi-dev

README.md

@@ -6,7 +6,7 @@
 | [ 없는 숫자 더하기 ](https://school.programmers.co.kr/learn/courses/30/lessons/86051) | Level1 | [🍉](https://github.com/hwangJi-dev/swiftAlgorithm/blob/main/ProgrammersLevel1/ProgrammersLevel1/7-NoneNumberPlus/solve.swift) | [ 💬 #4 ](https://github.com/hwangJi-dev/swiftAlgorithm/issues/4)|
 | [ 신규 아이디 추천 ](https://school.programmers.co.kr/learn/courses/30/lessons/72410?language=swift) | Level1 | [🍉](https://github.com/hwangJi-dev/swiftAlgorithm/blob/main/ProgrammersLevel1/ProgrammersLevel1/%EC%8B%A0%EA%B7%9C%20%EC%95%84%EC%9D%B4%EB%94%94%20%EC%B6%94%EC%B2%9C.swift) | [ 💬 #5 ](https://github.com/hwangJi-dev/swiftAlgorithm/blob/main/stringPractice/stringPractice/main.swift) |
 | [ 키패드 누르기 ](https://school.programmers.co.kr/learn/courses/30/lessons/67256) | Level1 | [🍉](https://github.com/hwangJi-dev/swiftAlgorithm/blob/main/ProgrammersLevel1/ProgrammersLevel1/%ED%82%A4%ED%8C%A8%EB%93%9C%20%EB%88%84%EB%A5%B4%EA%B8%B0.swift) | [ 💬 #6 ](https://github.com/hwangJi-dev/swiftAlgorithm/issues/6) |
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+| [ 가운데 글자 가져오기 ](https://school.programmers.co.kr/learn/courses/30/lessons/12903) | Level1 | [🍉](https://github.com/hwangJi-dev/swiftAlgorithm/blob/main/ProgrammersLevel1/ProgrammersLevel1/%EA%B0%80%EC%9A%B4%EB%8D%B0%20%EA%B8%80%EC%9E%90%20%EA%B0%80%EC%A0%B8%EC%98%A4%EA%B8%B0.swift) | [ 💬 #7 ](https://github.com/hwangJi-dev/swiftAlgorithm/issues/7) |
 
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