Update CHANGES

Co-authored-by: Oliver Beckstein <orbeckst@gmail.com>

Author: xiki-tempula

CHANGES

@@ -20,7 +20,7 @@ The rules for this file:
 Changes
   - Drop support for py3.7 (Issue #179, PR #214)
   - forward_backward_convergence will use AutoMBAR as backend when `MBAR` is
-  selected as the estimator (PR #114).
+    selected as the estimator (PR #114).
   - AutoMBAR accepts the `method` argument (PR #114).
 
 Enhancements