chore: bump version to 2.0.51 update changelog

as title

Log: as title

Author: caixr23

debian/changelog

@@ -1,3 +1,9 @@
+dde-network-core (2.0.51) unstable; urgency=medium
+
+  * fix: Modify network service crash issue
+
+ -- caixiangrong <caixiangrong@uniontech.com>  Thu, 20 Mar 2025 17:42:20 +0800
+
 dde-network-core (2.0.50) unstable; urgency=medium
 
   * fix: Record the last proxy method