perserve header ordering in yaml output

pyproject.toml

@@ -1,6 +1,6 @@
 [tool.poetry]
 name = 'dnd-rolltable'
-version = '1.1.4'
+version = '1.1.5'
 license = 'The Unlicense'
 authors = ['Greg Boyington <evilchili@gmail.com>']
 description = 'Generate roll tables using weighted random distributions'

rolltable/tables.py

@@ -102,7 +102,7 @@ class RollTable:
             cols = row[1:] + [''] * (len(self.headers) - len(row[1:]))
             for idx, col in enumerate(cols):
                 struct[row[0]][self.headers[idx] if idx < len(self.headers) else '_'] = col
-        return yaml.dump(struct)
+        return yaml.dump(struct, sort_keys=False)
 
     @property
     def die(self) -> int: