use the shared Buildx error summary helper

Signed-off-by: CrazyMax <1951866+crazy-max@users.noreply.github.com>

src/main.ts

@@ -166,8 +166,8 @@ actionsToolkit.run(
             // if there are no warnings found, return the first line of stdout
             err = Error(res.stdout.split('\n')[0]?.trim());
           }
-        } else if (res.stderr.length > 0) {
-          err = Error(`buildx bake failed with: ${res.stderr.match(/(.*)\s*$/)?.[0]?.trim() ?? 'unknown error'}`);
+        } else {
+          err = Error(`buildx bake failed with: ${Buildx.getErrorMessage(res.stderr)}`);
         }
       }
     });