chore(deps): update dependency celery to v5.6.1 (#4010)

Co-authored-by: renovate[bot] <29139614+renovate[bot]@users.noreply.github.com>

Author: renovate[bot]

requirements.txt

@@ -5,7 +5,7 @@ altcha==1.0.0
 argon2-cffi==25.1.0
 borgbackup==1.4.3
 boto3==1.42.18
-celery==5.6.0
+celery==5.6.1
 certifi==2025.11.12
 # For Argon2 and misaka
 cffi==2.0.0