Suppress flake8 A005 in existing API (#15)

This is a new check, and addressing the check's concern would change the
public API of the package. Suppress the existing violation specifically
and continue using the check to prevent new code from violating the
rule.

setup.cfg

@@ -70,6 +70,8 @@ colcon_core.verb =
 
 [flake8]
 import-order-style = google
+per-file-ignores =
+    colcon_alias/logging.py:A005
 
 [coverage:run]
 source = colcon_alias