web: convert changelogs from old format

https://gist.github.com/dumbmoron/3fc6c0c747d791928aba939976fd9304

web/changelogs/3.6.3.md

@@ -0,0 +1,14 @@
+---
+title: "less disturbance"
+---
+changelog popup no longer annoys you after a major update! this action has been replaced with a notification dot. if you see a red dot, then there's something new.
+
+your old setting that disabled the changelog popup now applies to notifications.
+
+new users will see a notification dot instead of an about popup, too. this was mostly done to prevent complications if your browser is set up to clean local storage when you close it.
+
+other changes:
+- popups are now a bit wider, just so more content fits at once.
+- better interface scaling.
+- code is a bit cleaner now.
+- changed twitter api endpoint. there should no longer be any rate limits.