chore: bump version to 6.0.31

update changelog to 6.0.31

Author: mhduiy

debian/changelog

@@ -1,3 +1,10 @@
+dde-api (6.0.31) unstable; urgency=medium
+
+  * fix: update linker flags for enhanced security hardening
+  * fix: handle nil URL parsing result for colon-containing filenames
+
+ -- zhangkun <[email protected]>  Thu, 18 Dec 2025 19:46:19 +0800
+
 dde-api (6.0.30) unstable; urgency=medium
 
   * fix: 修复dde-open识别不了空文件的问题