sort and indent version record files

See #161.

nvchecker/__init__.py

@@ -1,4 +1,4 @@
 # MIT licensed
 # Copyright (c) 2013-2020 lilydjwg <lilydjwg@gmail.com>, et al.
 
-__version__ = '2.1'
+__version__ = '2.2dev'

nvchecker/core.py

@@ -132,7 +132,12 @@ def read_verfile(file: Path) -> VersData:
   return v
 
 def write_verfile(file: Path, versions: VersData) -> None:
-  data = json.dumps(versions, ensure_ascii=False) + '\n'
+  # sort and indent to make it friendly to human and git
+  data = json.dumps(
+    dict(sorted(versions)),
+    indent=2,
+    ensure_ascii=False,
+  ) + '\n'
   safe_overwrite(str(file), data)
 
 class Options(NamedTuple):