ci: fix package_core

Author: facchinm

.github/workflows/package_core.yml

@@ -6,15 +6,18 @@ jobs:
   build:
     runs-on: ubuntu-latest
     env:
-      ZEPHYR_SDK_INSTALL_DIR: /home/runner/work/ArduinoCore-zephyr/zephyr-sdk-0.16.8
+      ZEPHYR_SDK_INSTALL_DIR: /opt/zephyr-sdk-0.16.8
     steps:
       - name: Install toolchain
+        working-directory: /opt
         run: |
           sudo apt-get update
           sudo apt-get install -y --no-install-recommends git cmake wget python3-pip
           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
 
+      - uses: actions/checkout@v4
+
       - name: Initialize
         run: |
           ./extra/bootstrap.sh