chore: update changelog template

.release-plz.toml

@@ -2,8 +2,39 @@
 dependencies_update = true # update dependencies with `cargo update`
 
 [changelog]
-header = "# Changelog"
-body = "Body"
+header = """# Changelog
+
+All notable changes to this project will be documented in this file.
+
+The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
+and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
+
+## [Unreleased]
+"""
+
+body = """
+
+## [{{ version | trim_start_matches(pat="v") }}]\
+    {%- if release_link -%}\
+        ({{ release_link }})\
+    {% endif %} \
+    - {{ timestamp | date(format="%Y-%m-%d") }}
+{% for group, commits in commits | group_by(attribute="group") %}
+### {{ group | upper_first }}
+    {% for commit in commits %}
+        {%- if commit.scope -%}
+            - *({{commit.scope}})* {% if commit.breaking %}[**breaking**] {% endif %}\
+                {{ commit.message }}\
+                {%- if commit.links %} \
+                    ({% for link in commit.links %}[{{link.text}}]({{link.href}}) {% endfor -%})\
+                {% endif %}
+        {% else -%}
+            - {% if commit.breaking %}[**breaking**] {% endif %}{{ commit.message }}
+        {% endif -%}
+    {% endfor -%}
+{% endfor %}
+"""
+
 trim = true
 protect_breaking_commits = true
 sort_commits = "newest"