chore: Add git-cliff as a changelog generation tool

Changelogs will be generated using commit messages by
`scripts/release.py`.

Both the commit message and the PR title should follow https://conventionalcommits.org. E.g. start with 'feat:' (for Features / Changes), 'fix:' (for Fixes), 'api:' (for API-Changes), 'api!:' for breaking API-Changes) 'refactor:' (for Refactor), 'perf:' (for Performance), 'test:' (for Tests), 'style:' (for Styling), 'chore:' (for Miscellaneous Tasks)

scripts/release.py

@@ -0,0 +1,39 @@
+#!/usr/bin/env python3
+
+import sys
+import subprocess
+import set_core_version
+from argparse import ArgumentParser
+
+
+# update the version
+parser = ArgumentParser(prog="release")
+parser.add_argument("newversion")
+
+try:
+    newversion = parser.parse_args().newversion
+except SystemExit:
+    newversion = None
+set_core_version.set_version(newversion)
+
+tag = "v" + newversion
+
+# TODO would be nice to automatically checkout the correct branch
+
+# update the changelog
+print(f"Updating CHANGELOG.md using git cliff --unreleased --tag {newversion} --prepend CHANGELOG.md")
+changelog = subprocess.run(["git", "cliff", "--unreleased", "--tag", newversion, "--prepend", "CHANGELOG.md"]).stdout.strip()
+subprocess.run(["git", "add", "-A"])
+subprocess.run(["git", "commit", "-m", f"chore(release): prepare for {tag}"])
+subprocess.run(["git", "show"])
+
+# create a tag
+subprocess.run(
+    [
+        "git", "tag", "-a", tag, "-m", f"Release {tag}", "-m", changelog
+    ]
+)
+subprocess.run(["git", "tag", "-v", tag])
+
+print("Done!")
+print(f"Now push the commit (git push origin {tag}).")