Release v1.7.3 (#526)

diff --git a/CHANGELOG b/CHANGELOG
index 0426d39..eb4afea 100644
--- a/CHANGELOG
+++ b/CHANGELOG
@@ -1,3 +1,11 @@
+v1.7.3
+  Version 1.7.3
+
+  Bugfix release
+
+  - Make apiclient.sample_tools gracefully fail to import (#525).
+
+
 v1.7.2
   Version 1.7.2