Add Changelog with v0.2.0 info

Signed-off-by: Sam Friedman <sam@golioth.io>

Author: sam-golioth

CHANGELOG.md

@@ -0,0 +1,12 @@
+# [0.2.0] 2025-10-13
+
+## Added
+- CI tests using BabbleSim
+- WiFi support for the FRDM-RW612 board
+- Support for the 16-bit Pouch Service UUID
+- Support for using indications for Uplink
+
+## Fixed
+- Thingy91:X appcore artifacts are now included in release binaries and
+  instructions
+- Fixed timeouts when creating new blocks