chore(deps): update dependency boto3 to v1.42.15

Author: renovate[bot]

requirements.txt

@@ -4,7 +4,7 @@ aliyun-python-sdk-alimt==3.2.0
 altcha==1.0.0
 argon2-cffi==25.1.0
 borgbackup==1.4.3
-boto3==1.42.14
+boto3==1.42.15
 celery==5.6.0
 certifi==2025.11.12
 # For Argon2 and misaka