Updated Creating a release (markdown)

Creating-a-release.md

@@ -1,7 +1,7 @@
 - ensure travis and appveyor is green (Usually the case these days) for the release branch 0-19, 0-20, etc
 
-- Update the version
-  - In system.nim
+- Update the version in system.nim
+- Update the changelog (put the release date, copy it to e.g. `changelog_0_20_0.md`)
 - Tag the release, e.g. ```git tag -am "Version 0.15.0" v0.15.0```
 - Push the tag: ```git push origin [tagname]```