Fix typo for debug message

aeri_qc/main.py

@@ -348,7 +348,7 @@ def files_to_update(cxs_files, qc_dir, *, force=False, hint=None):
     Find a matching SUM file and determine the QC filename for each CXS file in sequence
     """
     if not os.path.isdir(qc_dir):
-        LOG.debug('Creating output directory: $s', qc_dir)
+        LOG.debug('Creating output directory: %s', qc_dir)
         os.mkdir(qc_dir)
     for cxs_file in cxs_files:
         # Determine names of possible files