CHANGELOG: start drafting for v0.2.0

CHANGELOG.md

@@ -2,6 +2,20 @@
 
 ## Unreleased
 
+This release of Garble drops support for Go 1.15.x, which is necessary for some
+of the enhancements below:
+
+* `garble test` allows running Go tests built with obfuscation
+* `garble reverse` allows de-obfuscating output like stack traces
+* Names of functions implemented in assembly are now obfuscated
+* `GOPRIVATE=*` now works with packages like `crypto/tls` and `embed`
+
+The README is also overhauled to be more helpful to first-time users.
+
+Known bugs:
+
+* obfuscating the standard library with `GOPRIVATE=*` is not well supported yet
+
 ## [0.1.0] - 2021-03-05
 
 This is the first release of Garble. It supports Go 1.15.x and 1.16.x.