Add changelog entry.

CHANGELOG.md

@@ -164,6 +164,8 @@ Changes in Coq:
 * Make direction of `f_op` rewrite lemmas more consistent: Flip `pair_op`,
   `Cinl_op`, `Cinr_op`, `cmra_morphism_op`, `cmra_morphism_pcore`,
   `cmra_morphism_core`.
+* Rename lemmas `fupd_big_sep{L,M,S,MS}` into `big_sep{L,M,S,MS}_fupd` to be
+  consistent with other such big op lemmas. Also add such lemmas for `bupd`.
 * Rename `C` suffixes into `O` since we no longer use COFEs but OFEs. Also
   rename `ofe_fun` into `discrete_fun` and the corresponding notation `-c>` into
   `-d>`. The renaming can be automatically done using the following script (on