Bump to v6.2.0, add missing release dates to changelog, update copyright year

content/_index.md

@@ -66,7 +66,7 @@ It is highly recommended to switch from the `main` branch to the latest release:
 
 ```bash
 cd themes/duckquill
-git checkout tags/v6.1.1
+git checkout tags/v6.2.0
 ```
 
 Then, enable it in your `config.toml`:
@@ -80,7 +80,7 @@ To update the theme, simply switch to a new tag:
 ```bash
 git submodule update --remote --merge
 cd themes/duckquill
-git checkout tags/v6.1.1
+git checkout tags/v6.2.0
 ```
 
 {% alert(important=true) %}