Remove support for 'PW_FORMAT' environment variable

This highlights an issue with 'sphinx-click' [1]. Said issue is resolved
with sphinx-click 1.4.1 but that's not available on Fedora, so we simply
ignore this for now.

[1] click-contrib/sphinx-click#26

Signed-off-by: Stephen Finucane <[email protected]>

Author: stephenfin

Diff for: git_pw/utils.py

@@ -171,8 +171,7 @@ def format_options(original_function=None, headers=None):
     """Shared output format options."""
 
     def _format_options(f):
-        f = click.option('--format', '-f', 'fmt', envvar='PW_FORMAT',
-                         default=None,
+        f = click.option('--format', '-f', 'fmt', default=None,
                          type=click.Choice(['simple', 'table', 'csv']),
                          help="Output format. Defaults to the value of "
                          "'git config pw.server' else 'table'.")(f)