Update CHANGELOG.md

CHANGELOG.md

@@ -6,6 +6,8 @@
 - Travis now runs [shellcheck](https://github.com/koalaman/shellcheck) on every commit and pull request.
     - We've had to exclude around 10 lint errors, see this wiki page for why we did this:
     - https://github.com/dylanaraps/neofetch/wiki/Shellcheck-Exclusions
+- Optimize usage of get_de(), get_wm() and get_term().
+    - We were calling these multiple times, we now check to see if they were run previously.
 
 ## Images