ci: fix package_core

Author: facchinm

.github/workflows/package_core.yml

@@ -12,7 +12,7 @@ jobs:
         working-directory: /opt
         run: |
           sudo apt-get update
-          sudo apt-get install -y --no-install-recommends git cmake wget python3-pip
+          sudo apt-get install -y --no-install-recommends git cmake wget python3-pip ninja-build
           wget https://github.com/zephyrproject-rtos/sdk-ng/releases/download/v0.16.8/zephyr-sdk-0.16.8_linux-x86_64_minimal.tar.xz
           tar xf zephyr-sdk-0.16.8_linux-x86_64_minimal.tar.xz && cd zephyr-sdk-0.16.8 && ./setup.sh -t arm-zephyr-eabi -c