SOLR-17619 changes2html.py support release without release-date

Author: janhoy

gradle/documentation/changes-to-html/changes2html.py

@@ -31,7 +31,7 @@
 class ChangelogParser:
     """Parse CHANGELOG.md generated by logchange"""
 
-    RELEASE_PATTERN = re.compile(r'^\[(\d+(?:\.\d+)*)\]\s*-\s*(.+)$')
+    RELEASE_PATTERN = re.compile(r'^\[(\d+(?:\.\d+)*)\](\s+-\s+(.+))?$')
     SECTION_PATTERN = re.compile(r'^###\s+(\w+(?:\s+\w+)*)\s*(?:\(\d+\s+changes?\))?')
     ITEM_PATTERN = re.compile(r'^###|^\[|^- ')
 
@@ -80,7 +80,7 @@ def parse(self, content):
 
                 current_release = {
                     'version': match.group(1),
-                    'date': match.group(2).strip(),
+                    'date': match.group(3).strip() if match.group(3) else None,
                     'sections': []
                 }
                 current_section = None