Logging error

I'm using python 3.7.7, sphinx 3.0.3 and the latest automodapi.

The following problem occurs:
I get these kind of warnings:
"WARNING: Found additional options members in automodapi"
however it causes a logging error:
TypeError: not all arguments converted during string formatting

I played around with it and I could fix it by this, as it seems that arguments are passed to the string that have no % formatter placeholders:

```
Index: automodapi.py
===================================================================
--- automodapi.py (revision 34799)
+++ automodapi.py (working copy)
@@ -286,7 +286,7 @@
# tell sphinx that the remaining args are invalid.
if len(unknownops) > 0 and app is not None:
opsstrs = ','.join(unknownops)
- msg = 'Found additional options ' + opsstrs + ' in automodapi.'
+ msg = 'Found additional options ' + opsstrs + ' in automodapi. %s'
if warnings:
logger.warning(msg, location)
```

Start by reproducing the warning with Python 3.7.7, Sphinx 3.0.3, and the latest automodapi. Inspect automodapi.py around the reported warning code and logging call. Done means the additional-options warning is emitted without the logging TypeError.

Written by the indexing model from the issue text.