flake8: add explicit stacklevel to warn() calls

Author: an-ky

testinfra/main.py

@@ -16,5 +16,5 @@
 
 
 def main():
-    warnings.warn("calling testinfra is deprecated, call py.test instead")
+    warnings.warn("calling testinfra is deprecated, call py.test instead", stacklevel=1)
     return pytest.main()

testinfra/modules/pip.py

@@ -147,7 +147,8 @@ def _deprecated():
         """Raise a `DeprecationWarning`"""
         warnings.warn(
             "Calling host.pip_package is deprecated, call host.pip instead",
-            DeprecationWarning,
+            category=DeprecationWarning,
+            stacklevel=2,
         )
 
     @classmethod