Git-Action: Update Readme

Author: thelightway24

README.md

@@ -70,6 +70,7 @@
 | 25083 | [25083. 새싹](./%EB%B0%B1%EC%A4%80/Bronze/25083.%E2%80%85%EC%83%88%EC%8B%B9) |
 | 25304 | [25304. 영수증](./%EB%B0%B1%EC%A4%80/Bronze/25304.%E2%80%85%EC%98%81%EC%88%98%EC%A6%9D) |
 | 25314 | [25314. 코딩은 체육과목 입니다](./%EB%B0%B1%EC%A4%80/Bronze/25314.%E2%80%85%EC%BD%94%EB%94%A9%EC%9D%80%E2%80%85%EC%B2%B4%EC%9C%A1%EA%B3%BC%EB%AA%A9%E2%80%85%EC%9E%85%EB%8B%88%EB%8B%A4) |
+| 27866 | [27866. 문자와 문자열](./%EB%B0%B1%EC%A4%80/Bronze/27866.%E2%80%85%EB%AC%B8%EC%9E%90%EC%99%80%E2%80%85%EB%AC%B8%EC%9E%90%EC%97%B4) |
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