Add 0d6031e4 to the changelog.

CHANGELOG.md

@@ -3,6 +3,12 @@ way the logic is used on paper.  We also mention some significant changes in the
 Coq development, but not every API-breaking change is listed.  Changes marked
 `[#]` still need to be ported to the Iris Documentation LaTeX file(s).
 
+## Iris master
+
+Changes in Coq:
+
+* Rename `timelessP` -> `timeless` (projection of the `Timeless` class)
+
 ## Iris 3.1.0 (released 2017-12-19)
 
 Changes in and extensions of the theory: