Update changelog for v5.2.1

Author: JonasAlfredsson

docs/changelog.md

@@ -1,5 +1,8 @@
 # Changelog
 
+### 5.2.1
+- Update certbot to v2.11.0.
+
 ### 5.2.0
 - Forward the `SIGUSR1` signal to Nginx to tell it to reopen log files.
   - PR by [@fredrikekre][50]

docs/dockerhub_tags.md

@@ -17,7 +17,8 @@ are updated.
 
 | Major | Minor | Patch | Nginx              |
 | ----: | ----: | ----: | :----------------- |
-| 5     | 5.2   | 5.2.0 | 5.2.0-nginx1.27.0  |
+| 5     | 5.2   | 5.2.1 | 5.2.1-nginx1.27.0  |
+|       |       | 5.2.0 | 5.2.0-nginx1.27.0  |
 |       |       |       | 5.2.0-nginx1.26.0  |
 |       | 5.1   | 5.1.1 | 5.1.1-nginx1.26.0  |
 |       |       | 5.1.0 | 5.1.0-nginx1.26.0  |