chore(deps): update vexxhost/docker-atmosphere digest to ec6b988

Signed-off-by: renovate[bot] <29139614+renovate[bot]@users.noreply.github.com>

Author: renovate[bot]

.github/workflows/build.yml

@@ -17,7 +17,7 @@ jobs:
       packages: write
       pull-requests: write
     steps:
-      - uses: vexxhost/docker-atmosphere/.github/actions/build-image@9dc904e06dcde958bf8a0b3230715d32b9e3a85f # main
+      - uses: vexxhost/docker-atmosphere/.github/actions/build-image@ec6b988f3cace4eb90d19efe81ab3992ad54251b # main
         with:
           image-name: python-openstackclient
           push: ${{ github.event_name != 'pull_request' }}