ci: remove DockerHub logins

Author: jameslamb

.github/workflows/build-and-test.yml

@@ -149,13 +149,6 @@ jobs:
           username: ${{ github.repository_owner }}
           password: ${{ github.token }}
 
-      - &login_dockerhub
-        name: Login to DockerHub
-        uses: docker/login-action@c94ce9fb468520275223c153574b00df6fe4bcc9  # v3.7.0
-        with:
-          username: ${{ secrets.GPUCIBOT_DOCKERHUB_USER }}
-          password: ${{ secrets.GPUCIBOT_DOCKERHUB_TOKEN }}
-
       - name: Build and push Velox deps image
         id: push
         uses: docker/build-push-action@263435318d21b8e681c14492fe198d362a7d2c83  # v6.18.0