Use environment variable to define build folder name in release workflow

Multiple commands in the release workflow include the path of the folder that contains the build output. Previously,
the complex folder name was specified redundantly in each instance.

The readability and maintainability of the workflow is improved by using an environment variable to define the folder
name in a single place, then referencing that environment variable in each of the individual commands that use the path.

Author: per1234

.github/workflows/release-go-crosscompile-task.yml

@@ -91,6 +91,10 @@ jobs:
             package-suffix: "macOS_ARM64.tar.gz"
 
     steps:
+      - name: Set environment variables
+        run: |
+          # See: https://docs.github.com/actions/writing-workflows/choosing-what-your-workflow-does/workflow-commands-for-github-actions#setting-an-environment-variable
+          echo "BUILD_FOLDER=${{ env.PROJECT_NAME }}_osx_${{ matrix.build.folder-suffix }}" >> "$GITHUB_ENV"
       - name: Checkout repository
         uses: actions/checkout@v4
 
@@ -133,7 +137,7 @@ jobs:
         run: |
           cat > "${{ env.GON_CONFIG_PATH }}" <<EOF
           # See: https://github.com/Bearer/gon#configuration-file
-          source = ["${{ env.DIST_DIR }}/${{ env.PROJECT_NAME }}_osx_${{ matrix.build.folder-suffix }}/${{ env.PROJECT_NAME }}"]
+          source = ["${{ env.DIST_DIR }}/${{ env.BUILD_FOLDER }}/${{ env.PROJECT_NAME }}"]
           bundle_id = "cc.arduino.${{ env.PROJECT_NAME }}"
 
           sign {
@@ -162,10 +166,10 @@ jobs:
         run: |
           # GitHub's upload/download-artifact actions don't preserve file permissions,
           # so we need to add execution permission back until the action is made to do this.
-          chmod +x "${{ env.PROJECT_NAME }}_osx_${{ matrix.build.folder-suffix }}/${{ env.PROJECT_NAME }}"
+          chmod +x "${{ env.BUILD_FOLDER }}/${{ env.PROJECT_NAME }}"
           TAG="${GITHUB_REF/refs\/tags\//}"
           PACKAGE_FILENAME="${{ env.PROJECT_NAME }}_${TAG}_${{ matrix.build.package-suffix }}"
-          tar -czvf "$PACKAGE_FILENAME" "${{ env.PROJECT_NAME }}_osx_${{ matrix.build.folder-suffix }}/"
+          tar -czvf "$PACKAGE_FILENAME" "${{ env.BUILD_FOLDER }}/"
           echo "PACKAGE_FILENAME=$PACKAGE_FILENAME" >> $GITHUB_ENV
 
       - name: Upload artifact