Reformat changelog does not support unnamed section

[oddstr13]

Traceback (most recent call last):
  File "/home/runner/work/jellyfin-kodi/jellyfin-kodi/.github/tools/reformat_changelog.py", line 87, in <module>
    reformat(args.format, args.emoji)
  File "/home/runner/work/jellyfin-kodi/jellyfin-kodi/.github/tools/reformat_changelog.py", line 49, in reformat
    section["items"].append(gd)
KeyError: 'items'

https://github.com/jellyfin/jellyfin-kodi/actions/runs/6033384710/job/16369981650#step:5:56

jellyfin-kodi/.github/tools/reformat_changelog.py

Lines 33 to 49 in 68c49ea

	section: Union[SectionType, Dict] = {}
	for line in data:
	if line.startswith("## "):
	pass
	if line.startswith("### "):
	if section:
	sections.append(section)
	_section: SectionType = {
	"title": line.strip("# "),
	"items": [],
	}
	section = _section
	m = ITEM_PATTERN.match(line)
	if m:
	gd = m.groupdict()
	section["items"].append(gd)