chore: Update release-plz.toml

Author: makspll

release-plz.toml

@@ -7,7 +7,7 @@ git_release_body = """
 {{ changelog }}
 {% if remote.contributors %}
 ### Contributors
-{% for contributor in remote.contributors %}
+{% for contributor in remote.contributors | unique(attribute="username") %}
 * @{{ contributor.username }}
 {% endfor %}
 {% endif %}