doc: Fixed consistency of MCUboot

Fixed the consistency of the case used in the term MCUboot.

Signed-off-by: Francesco Servidio <francesco.servidio@nordicsemi.no>
diff --git a/docs/readme-zephyr.md b/docs/readme-zephyr.md
index 26bc519..53179b4 100644
--- a/docs/readme-zephyr.md
+++ b/docs/readme-zephyr.md
@@ -32,10 +32,10 @@
 
 ## Installing Requirements and Dependencies
 
-Install additional packages required for development with mcuboot:
+Install additional packages required for development with MCUboot:
 
 ```
-  cd ~/mcuboot  # or to your directory where mcuboot is cloned
+  cd ~/mcuboot  # or to your directory where MCUboot is cloned
   pip3 install --user -r scripts/requirements.txt
 ```