Initial `towncrier` integration for releases

Add a small config with a manually specified version key for now.
Fix up some changelog contents from last release and bump our `setup.py`
version to an `.alpha2.dev0`.

Resolves #227

NEWS.rst

@@ -2,6 +2,8 @@
 Changelog
 =========
 
+.. towncrier release notes start
+
 tractor 0.1.0a1 (2021-08-01)
 ============================
 
@@ -9,9 +11,10 @@ Features
 --------
 - Updated our uni-directional streaming API (`#206
   <https://github.com/goodboy/tractor/pull/206>`_) to require a context
-  manager style ``async Portal.stream_from(target) as stream:`` which
-  explicitly determines when to stop a stream in the calling (aka portal
-  opening) actor much like ``async_generator.aclosing()`` enforcement.
+  manager style ``async with Portal.open_stream_from(target) as stream:``
+  which explicitly determines when to stop a stream in the calling (aka
+  portal opening) actor much like ``async_generator.aclosing()``
+  enforcement.
 
 - Improved the ``multiprocessing`` backend sub-actor reaping (`#208
   <https://github.com/goodboy/tractor/pull/208>`_) during actor nursery
@@ -36,9 +39,9 @@ Experiments and WIPs
   land by next release.
 
 - Improved "infect ``asyncio``" cross-loop task cancellation and error
-  propagation by vastly simplifying the approach.  We may end up just
-  going with a use of ``anyio`` in the medium term to avoid re-doing
-  work done by that group cross-event-loop portals.  See the
+  propagation by vastly simplifying the cross-loop-task streaming approach. 
+  We may end up just going with a use of ``anyio`` in the medium term to
+  avoid re-doing work done by their cross-event-loop portals.  See the
   ``infect_asyncio`` for details.
 
 
@@ -67,7 +70,7 @@ Trivial/Internal Changes
 - Added a new ``TransportClosed`` internal exception/signal (`#215
   <https://github.com/goodboy/tractor/pull/215>`_ for catching TCP
   channel gentle closes instead of silently falling through the message
-  handler loop via an async generator ``return```.
+  handler loop via an async generator ``return``.
 
 
 Deprecations and Removals

newsfragments/.gitignore

@@ -0,0 +1 @@
+!.gitignore

setup.py

@@ -24,7 +24,7 @@ with open('docs/README.rst', encoding='utf-8') as f:
 
 setup(
     name="tractor",
-    version='0.1.0a1',  # first ever alpha
+    version='0.1.0a2.dev0',  # alpha zone
     description='structured concurrrent "actors"',
     long_description=readme,
     license='GPLv3',

towncrier.toml

@@ -0,0 +1,7 @@
+[tool.towncrier]
+package = "tractor"
+filename = "NEWS.rst"
+directory = "newsfragments/"
+title_format = "tractor {version} ({project_date})"
+version = "0.1.0a2"
+#template = "changelog/_template.rst"