invoke: Use invoke_cleanup as installed package

Author: jenisys

tasks/__init__.py

@@ -27,7 +27,7 @@
 from invoke import Collection
 
 # -- TASK-LIBRARY:
-from . import invoke_cleanup as cleanup
+import invoke_cleanup as cleanup
 from . import docs
 from . import test
 

tasks/docs.py

@@ -11,7 +11,7 @@
 from path import Path
 
 # -- TASK-LIBRARY:
-from .invoke_cleanup import cleanup_tasks, cleanup_dirs
+from invoke_cleanup import cleanup_tasks, cleanup_dirs
 
 
 # -----------------------------------------------------------------------------