Changed the image for tests on linux arm

Author: Andrey Senyaev

.github/workflows/build_wheels_linux_arm.yml

@@ -43,7 +43,7 @@ jobs:
       TRAVIS_BUILD_DIR: ${{ github.workspace }}
       CONFIG_PATH: travis_config.sh
       DOCKER_IMAGE: quay.io/asenyaev/manylinux2014_${PLAT}
-      DOCKER_TEST_IMAGE: multibuild/xenial_arm64v8
+      DOCKER_TEST_IMAGE: multibuild/focal_arm64v8
       USE_CCACHE: 0
       UNICODE_WIDTH: 32
       SDIST: ${{ matrix.build_sdist || 0 }}