Check extensions on changelog fragments.

test/sanity/code-smell/changelog.py

@@ -1,11 +1,21 @@
 #!/usr/bin/env python
 
+import os
 import sys
 import subprocess
 
 
 def main():
     paths = sys.argv[1:] or sys.stdin.read().splitlines()
+
+    allowed_extensions = ('.yml', '.yaml')
+
+    for path in paths:
+        ext = os.path.splitext(path)[1]
+
+        if ext not in allowed_extensions:
+            print('%s:%d:%d: extension must be one of: %s' % (path, 0, 0, ', '.join(allowed_extensions)))
+
     cmd = ['packaging/release/changelogs/changelog.py', 'lint'] + paths
     subprocess.check_call(cmd)