Fix file names

_data/signed/iamserje.yaml

@@ -1,2 +1,2 @@
 name: Serguei Voronkov
-link: iamserje@yandex.ru
+link: mailto:iamserje@yandex.ru

check-signatures-format.py

@@ -6,6 +6,9 @@ regex = re.compile(r"name: (\S+\s)*\S+\nlink: (/#|(https?://|mailto:)[a-zA-Z0-9_
 
 ok = True
 for file_name in sorted(os.listdir("_data/signed")):
+    if not file_name.endswith(".yaml") or file_name[:-5] != file_name[:-5].strip():
+        print(file_name, "has invalid name")
+        ok = False
     with open(f"_data/signed/{file_name}") as f:
         contents = f.read()
     if not re.fullmatch(regex, contents):