Add release date for v0.17.3

Viktor Lövgren · Viktor Lövgren · commit 4ecb2b010193 · 2018-12-10T20:22:37.000Z
diff --git a/notes/0.17.3.markdown b/notes/0.17.3.markdown
@@ -3,3 +3,5 @@
 - Add `withRequestTimeout` and `withDefaultApiTimeout` to `ConsumerSettings`. ([#59][#59])
 
 [#59]: https://github.com/ovotech/fs2-kafka/pull/59
+
+Released on 2018-12-10.
