doc: Update release notes for 1.9.0-rc2
Add notes on changes since rc1.
@@ -27,6 +27,10 @@ been tested with a `BOOT_MAX_ALIGN` up to 32 bytes.
- Add support for "partial multi-image booting"
- Add support for clear image generation with encryption capability to
imgtool
+- Fix Zephyr when `CONFIG_BOOT_ENCRYPTION_KEY_FILE` is not defined
+- Remove zephyr example test running in shell. The Go version is
+ primary and much more featureful.
+- imgtool: make `--max-align` default reasonable in most cases.
### Security fixes
