Fix for asyncio.iscoroutinefunction deprecation warnings

Closes #2512

Refs https://github.com/simonw/asyncinject/issues/18

datasette/utils/check_callable.py

@@ -1,4 +1,4 @@
-import asyncio
+import inspect
 import types
 from typing import NamedTuple, Any
 
@@ -17,9 +17,9 @@ def check_callable(obj: Any) -> CallableStatus:
         return CallableStatus(True, False)
 
     if isinstance(obj, types.FunctionType):
-        return CallableStatus(True, asyncio.iscoroutinefunction(obj))
+        return CallableStatus(True, inspect.iscoroutinefunction(obj))
 
     if hasattr(obj, "__call__"):
-        return CallableStatus(True, asyncio.iscoroutinefunction(obj.__call__))
+        return CallableStatus(True, inspect.iscoroutinefunction(obj.__call__))
 
     assert False, "obj {} is somehow callable with no __call__ method".format(repr(obj))

setup.py

@@ -58,7 +58,7 @@ setup(
         "mergedeep>=1.1.1",
         "itsdangerous>=1.1",
         "sqlite-utils>=3.30",
-        "asyncinject>=0.5",
+        "asyncinject>=0.6.1",
         "setuptools",
         "pip",
     ],