Add changelog management with towncrier

.changelog/template.md

+{% for section, _ in sections.items() %}
+{%- if section %}{{section}}{% endif -%}
+
+{% if sections[section] %}
+{% for category, val in definitions.items() if category in sections[section]%}
+### {{ definitions[category]['name'] }}
+
+{% if definitions[category]['showcontent'] %}
+{% for text, values in sections[section][category].items() %}
+- {{ values|join(', ') }} {{ text }}
+{% endfor %}
+
+{% else %}
+- {{ sections[section][category]['']|join(', ') }}
+
+{% endif %}
+{% if sections[section][category]|length == 0 %}
+No significant changes.
+
+{% else %}
+{% endif %}
+
+{% endfor %}
+{% else %}
+No significant changes.
+
+{% endif %}
+{% endfor %}

CHANGELOG.md

+
+
+# Changelog
+
+## 1.0.0 (2021-02-04)
+
+This is the first stable release. Its compatible to Funkwhale >= 1.0 and Mopidy >= 3.
+For a list of features, please see README

pyproject.toml

+[tool.towncrier]
+    package = "mopidy_funkwhale"
+    directory = ".changelog"
+    filename = "CHANGELOG.md"
+    all_bullets = true
+    template = ".changelog/changes/template.md"
+    start_string = "# Changelog\n"
+    issue_format = "[#{issue}](https://dev.funkwhale.audio/funkwhale/mopidy/-/issues/{issue})"
+    underlines = ["", ""]
+    title_format = "## {version} ({project_date})\n"
+