Union syntax compatibility with pre- Python 3.10 (#106)

We probably shouldn't be supporting EOL'd Pythons, but setup.py and
CONTRIBUTING.rst both say Python 3.6+ at this time, and the code does
not run on Python 3.6.

The easy fix for now is to use "from tying import Union"; a better fix
for the future would be to advance this project to Python 3.10+.

Author: rolandwalker

CHANGELOG

@@ -1,11 +1,12 @@
 # Changelog
 
-## Upcoming
+## Version 2.10.1
 
-(released on TBD)
+(released on 2025-02-18)
 
 - Update license dates.
 - Change `master` branch references to `main`.
+- Provisional Python 3.6 compatibility (Union syntax).
 
 ## Version 2.10.0
 

cli_helpers/utils.py

@@ -5,7 +5,7 @@
 import os
 import re
 from functools import lru_cache
-from typing import Dict
+from typing import Dict, Union
 
 from typing import TYPE_CHECKING
 
@@ -119,7 +119,7 @@ def replace(s, replace):
 
 
 @lru_cache()
-def _get_formatter(style) -> Terminal256Formatter | TerminalTrueColorFormatter:
+def _get_formatter(style) -> Union[Terminal256Formatter, TerminalTrueColorFormatter]:
     if "truecolor" in os.getenv("COLORTERM", "").lower():
         return TerminalTrueColorFormatter(style=style)
     else: