Turn coroutine to async def (#136)

* Turn coroutine to async def

* Update changelog

CHANGELOG.md

@@ -20,10 +20,15 @@ and this project adheres to [Semantic Versioning][semver].
 - Fix `__init__()` constructors in several interface types ([#125])
 - Fix valueSet type in `SymbolKindAbstract` ([#125])
 
+### Fixed
+
+- `coroutine` deprecation warning - use async def instead ([#136])
+
 [#125]: https://github.com/openlawlibrary/pygls/pull/125
 [#123]: https://github.com/openlawlibrary/pygls/pull/123
 [#120]: https://github.com/openlawlibrary/pygls/pull/120
 [#117]: https://github.com/openlawlibrary/pygls/pull/117
+[#136]: https://github.com/openlawlibrary/pygls/pull/136
 
 ## [0.9.0] - 04/20/2020
 

pygls/feature_manager.py

@@ -59,12 +59,14 @@ def wrap_with_server(f, server):
         return f
 
     if asyncio.iscoroutinefunction(f):
-        return asyncio.coroutine(functools.partial(f, server))
+        async def wrapped(*args, **kwargs):
+            return await f(server, *args, **kwargs)
     else:
         wrapped = functools.partial(f, server)
         if is_thread_function(f):
             assign_thread_attr(wrapped)
-        return wrapped
+
+    return wrapped
 
 
 class FeatureManager: