Update the changelog

Author: LHolten

CHANGELOG.md

@@ -1,3 +1,10 @@
+# 0.2.1
+
+- Relax `Transaction` creation to not borrow the `Database`.
+- Add missing lifetime bound on `try_insert`s return value. 
+Technically this is a breaking change, but it fixes a bug so it is still a patch release.
+- Fix the version of the macro crate exactly (=0.2.0) to allow future internal API changes with only a patch release.
+
 # 0.2.0
 
 - Rewrote almost the whole library to specify the schema using enum syntax with a proc macro.