Forgot to use f-string in error message about ` user_version > USER_VERSION`

[Steffen1989]

Checklist

• I added a descriptive title
• I searched open reports and couldn't find a duplicate

What happened?

I just ran into the problem when I try to use an old version of conda_index on a local conda channel I get this ValueError:

conda-index/conda_index/index/convert_cache.py

Lines 130 to 133 in 534bac6

	if user_version > USER_VERSION:
	raise ValueError(
	"conda-index cache is too new: version {user_version} > {USER_VERSION}"
	)

When I update conda-index to the latest version, everything works as expected.

To be a bit more informative, this error message should be an f-string, right?

Additional Context

No response