Add headings to changelog (#2333)

CHANGELOG.md

@@ -11,9 +11,12 @@ The minor version will be incremented upon a breaking change and the patch versi
 ## [Unreleased]
 
 ### Features
-
 - cli: Add `env` option to verifiable builds ([#2325](https://github.com/coral-xyz/anchor/pull/2325)).
 
+### Fixes
+
+### Breaking
+
 ## [0.26.0] - 2022-12-15
 
 ### Features