Support storing GHA outputs in specified .properties file

.github/workflows/custom-board-build/action.yaml

@@ -79,6 +79,10 @@ inputs:
     required: false
   EXTRA_LIVE_DATA_FILE:
     required: false
+  gha_outputs_file:
+    description: '.properties file to store GHA outputs (unfortunately GGA outputs do not work for nested GHA - see https://github.com/actions/runner/issues/2009#issuecomment-1793565031)'
+    required: false
+    default: 'false'
 
 runs:
   using: "composite"
@@ -160,6 +164,7 @@ runs:
         echo "white_label=$(bash ${{inputs.rusefi_dir}}/firmware/bin/find_white_label.sh shared_io.resources/shared_io.properties)" >> $GITHUB_OUTPUT
 
     - name: Set Env Variables
+      id: set-env-variables
       shell: bash
       run: |
         : Set Env Variables
@@ -534,3 +539,17 @@ runs:
       run: |
         : Upload Obfuscated Tagged Daily Release Bundle
         bash ../firmware/bin/upload_bundle.sh ${{ inputs.RUSEFI_OBFUSCATED_PUBLIC_SSH_USER }} "${{ inputs.RUSEFI_OBFUSCATED_PUBLIC_SSH_PASS }}" ${{ inputs.RUSEFI_OBFUSCATED_PUBLIC_SSH_SERVER }} "${{env.SHORT_BOARD_NAME}}_obfuscated_public" ${{ inputs.new_tag }}
+
+    - name: Create .properties file for action outputs
+      if: ${{ inputs.gha_outputs_file != ''}}
+      uses: 1arp/create-a-file-action@0.4.5
+      with:
+        file: ${{ inputs.gha_outputs_file }}
+
+    - name: Populate .properties file with action outputs
+      if: ${{ inputs.gha_outputs_file != ''}}
+      uses: kurt-code/gha-properties@v0.0.2
+      with:
+        operation: 'write'
+        file-path: ${{ inputs.gha_outputs_file }}
+        key-value-pairs: '{"white_label": "${{ steps.find-out-white-label.outputs.white_label }}", "short_board_name": "${{ steps.set-env-variables.outputs.short_board_name }}", "new_tag": "${{ steps.tag.outputs.new_tag }}"}'