run mypy with --install-types by default

Which allows to remove the dependency on types-pyyaml in [testing]
extra.

mypy.ini

 [mypy]
 namespace_packages = True
 warn_unused_ignores = True
-
+install_types = True
+non_interactive = True
 
 # 3rd party libraries without stubs (yet)
 
-
 [mypy-dulwich.*]
 ignore_missing_imports = True
 

requirements-test.txt

@@ -4,4 +4,3 @@ pytest-mock
 pyyaml
 swh.core[testing]
 swh.graph
-types-pyyaml