ci: Set workspace as a safe directory

This fixes an issue reported on
actions/checkout#760

Signed-off-by: Gustavo Henrique Nihei <[email protected]>

Author: gustavonihei

.github/workflows/build.yml

@@ -33,7 +33,9 @@ jobs:
       - name: Build MCUboot bootloader
         uses: docker://docker.io/espressif/idf:release-v4.4
         with:
-          args: ./build_mcuboot.sh -s -c ${{matrix.targets}}
+          args: |
+            git config --global --add safe.directory /github/workspace
+            ./build_mcuboot.sh -s -c ${{matrix.targets}}
       - uses: actions/upload-artifact@v3
         with:
           name: mcuboot-builds