Update changes for release 2.13.0

WilliamJamieson · WilliamJamieson · commit 389fb4b64216 · 2022-08-19T11:08:28.000-04:00
diff --git a/CHANGES.rst b/CHANGES.rst
@@ -1,4 +1,4 @@
-2.13.0 (unreleased)
+2.13.0 (2022-08-19)
 -------------------
 
 The ASDF Standard is at v1.6.0
