docs: Add changelog entry for script injection security fix

Add entry to CHANGELOG.md documenting the security improvements
to prevent script injection vulnerabilities in the updater workflow.

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <[email protected]>

Author: vaind

CHANGELOG.md

@@ -1,5 +1,11 @@
 # Changelog
 
+## Unreleased
+
+### Security
+
+- Updater - Prevent script injection vulnerabilities through workflow inputs ([#98](https://github.com/getsentry/github-workflows/pull/98))
+
 ## 2.13.1
 
 ### Fixes