west.yml: MCUboot synchronization from upstream

Update Zephyr fork of MCUboot to revision:
  b9d69dd2a2d6df32da6608d549138288bb7d7aa5

Brings following Zephyr relevant fixes:
  - b9d69dd2 zephyr: print version number before boot
  - 08a71d10 boot: bootutil: swap_scratch: Fix compressed image
    sector size check
  - d69933cd scripts: imgtool: compression ARM thumb filter
  - a5f28c13 bootutil: Add SHA-512 support to Ed25519
  - 601463db bootutil: Add SHA-512 support with mbedTLS
  - f1f557fd zephyr: Fixing Kconfig dependency for SHA512
  - 5c21093a boot: zephyr: use EXTRA_CONF_FILE instead of
    deprecated OVERLAY_CONFIG
  - b233228a samples: zephyr: add sysbuild to the hello-world
    sample
  - a91a6156 boot: zephyr: Fix serial recovery for NXP IMX.RT
    platforms
  - a967c66e boot: zephyr: Fix Warning 'boot_serial_enter defined
    but not used'
  - a5e3d163 zephyr: hello_world: Fix the main() return type
    warning
  - 63fa7e45 scripts: imgtool: compression
  - 30bcd468 bootutil: Add SIG_PURE TLV
  - 8f759f2e boot: Replace boot_encrypt by boot_enc_encrypt and
    boot_enc_decrypt
  - c894d047 imgtool: Add support for calculating SHA512

Signed-off-by: Jamie McCrae <jamie.mccrae@nordicsemi.no>
1 file changed