Bump dependencies (#874)

* fix pytest-asynio bump to 0.19

* bump mypy

* fix coverage of async fixtures

tests/test_deferred/test_same_table_joins.py

@@ -67,15 +67,8 @@ class Teacher(ormar.Model):
     category: Optional[Category] = ormar.ForeignKey(Category, nullable=True)
 
 
-@pytest.fixture(scope="module")
-def event_loop():
-    loop = asyncio.get_event_loop()
-    yield loop
-    loop.close()
-
-
 @pytest.fixture(autouse=True, scope="module")
-async def create_test_database():
+def create_test_database():
     engine = sqlalchemy.create_engine(DATABASE_URL)
     metadata.drop_all(engine)
     metadata.create_all(engine)