correct slashes

Author: davegarthsimpson

.github/workflows/build.yml

@@ -435,7 +435,8 @@ jobs:
         shell: bash
         run: |
           ARTIFACT=$(find "${{ env.BUILD_ARTIFACTS_PATH }}" -name "*Windows_64bit.exe" | head -n 1)
-          FULL_PATH=$(cygpath -w $ARTIFACT)
+          # Convert to Windows-style path with forward slashes
+          FULL_PATH=$(cygpath -w $ARTIFACT | sed 's|\\|/|g')
           echo "ARTIFACT_PATH=$FULL_PATH" >> $GITHUB_ENV
 
       - name: Save Win signing certificate to file