fix: update zephyr CONFIG_BOOTLOADER_MCUBOOT

Updates the zephyr CONFIG_BOOTLOADER_MCUBOOT documentation link to
target the new location.

Signed-off-by: Daniel Mangum <georgedanielmangum@gmail.com>
diff --git a/docs/readme-zephyr.md b/docs/readme-zephyr.md
index 96c1c09..2acc63d 100644
--- a/docs/readme-zephyr.md
+++ b/docs/readme-zephyr.md
@@ -92,10 +92,9 @@
 application; see samples/zephyr/README.md for a tutorial.
 
 The Zephyr `CONFIG_BOOTLOADER_MCUBOOT` configuration option
-[documentation](http://docs.zephyrproject.org/reference/kconfig/CONFIG_BOOTLOADER_MCUBOOT.html)
+[documentation](https://docs.zephyrproject.org/latest/kconfig.html#CONFIG_BOOTLOADER_MCUBOOT)
 provides additional details regarding the changes it makes to the image
-placement and generation in order for an application to be bootable by
-MCUboot.
+placement and generation in order for an application to be bootable by MCUboot.
 
 With this, build the application as your normally would.