Do not pin package tzdata anymore

tzdata is a timezone database that should always be upgradeable, otherwise other projects will run into dependency conflicts

Author: stollero

requirements/default.txt

@@ -1,4 +1,4 @@
 amqp>=5.1.1,<6.0.0
 vine==5.1.0
 backports.zoneinfo[tzdata]>=0.2.1; python_version<"3.9"
-tzdata==2025.2; python_version>="3.9"
+tzdata>=2025.2; python_version>="3.9"