chore(changelogs): add v2.6.0 changelog

Author: mboersma

mkdocs.yml

@@ -91,6 +91,7 @@ pages:
     - v2.4.1: changelogs/v2.4.1.md
     - v2.4.2: changelogs/v2.4.2.md
     - v2.5.0: changelogs/v2.5.0.md
+    - v2.6.0: changelogs/v2.6.0.md
 theme_dir: themes/deis
 docs_dir: src
 markdown_extensions: