Update "GPU Tests" status badge in README page (#1345)

README.md

@@ -6,7 +6,7 @@
 [![PyPI version](https://badge.fury.io/py/oumi.svg)](https://badge.fury.io/py/oumi)
 [![License](https://img.shields.io/badge/License-Apache%202.0-blue.svg)](https://opensource.org/licenses/Apache-2.0)
 [![Tests](https://github.com/oumi-ai/oumi/actions/workflows/pretest.yaml/badge.svg?branch=main)](https://github.com/oumi-ai/oumi/actions/workflows/pretest.yaml)
-[![GPU Tests](https://github.com/oumi-ai/oumi/actions/workflows/gpu_tests.yaml/badge.svg?branch=main)](https://github.com/oumi-ai/oumi/actions/workflows/gpu_tests.yaml)
+[![GPU Tests](https://github.com/oumi-ai/oumi/actions/workflows/gpu_tests.yaml/badge.svg)](https://github.com/oumi-ai/oumi/actions/workflows/gpu_tests.yaml)
 [![GitHub Repo stars](https://img.shields.io/github/stars/oumi-ai/oumi)](https://github.com/oumi-ai/oumi)
 [![Code style: black](https://img.shields.io/badge/code%20style-black-000000.svg)](https://github.com/psf/black)
 [![pre-commit](https://img.shields.io/badge/pre--commit-enabled-brightgreen?logo=pre-commit)](https://github.com/pre-commit/pre-commit)