Documentation: Add v2.20.9 changelog (#12200)

* Changelog v2.20.9 - GHA

* Update changelog for paperless-ngx 2.20.9

Added security advisory and bug fixes for version 2.20.9.

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Co-authored-by: github-actions <41898282+github-actions[bot]@users.noreply.github.com>
Co-authored-by: shamoon <4887959+shamoon@users.noreply.github.com>

docs/changelog.md

@@ -1,5 +1,25 @@
 # Changelog
 
+## paperless-ngx 2.20.9
+
+### Security
+
+-   Resolve [GHSA-386h-chg4-cfw9](https://github.com/paperless-ngx/paperless-ngx/security/advisories/GHSA-386h-chg4-cfw9)
+
+### Bug Fixes
+
+-   Fixhancement: config option reset [@shamoon](https://github.com/shamoon) ([#12176](https://github.com/paperless-ngx/paperless-ngx/pull/12176))
+-   Fix: correct page count by separating display vs collection sizes for tags [@shamoon](https://github.com/shamoon) ([#12170](https://github.com/paperless-ngx/paperless-ngx/pull/12170))
+
+### All App Changes
+
+<details>
+<summary>2 changes</summary>
+
+-   Fixhancement: config option reset [@shamoon](https://github.com/shamoon) ([#12176](https://github.com/paperless-ngx/paperless-ngx/pull/12176))
+-   Fix: correct page count by separating display vs collection sizes for tags [@shamoon](https://github.com/shamoon) ([#12170](https://github.com/paperless-ngx/paperless-ngx/pull/12170))
+</details>
+
 ## paperless-ngx 2.20.8
 
 ### Security