doc: Fix case in titles

Unified case in titles.
Fixed small grammar issues.

Signed-off-by: Francesco Servidio <francesco.servidio@nordicsemi.no>
diff --git a/docs/readme-zephyr.md b/docs/readme-zephyr.md
index 159c9c4..ea18fe9 100644
--- a/docs/readme-zephyr.md
+++ b/docs/readme-zephyr.md
@@ -30,7 +30,7 @@
 `boards/arm/frdm_k64f/frdm_k64f.dts`. Make sure the labels in your board's
 `.dts` file match the ones used there.
 
-## Installing Requirements and Dependencies
+## Installing requirements and dependencies
 
 Install additional packages required for development with MCUboot:
 
@@ -74,7 +74,7 @@
 memory (mass erase) or only the sectors where the bootloader resides prior to
 programming the bootloader image itself.
 
-## Building Applications for the bootloader
+## Building applications for the bootloader
 
 In addition to flash partitions in DTS, some additional configuration
 is required to build applications for MCUboot.