chore(deps): update ghcr.io/vexxhost/openstack-venv-builder:2023.1 docker digest to 21f3396 (#368)

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

Author: renovate[bot]

Dockerfile

@@ -2,7 +2,7 @@
 # SPDX-License-Identifier: GPL-3.0-or-later
 # Atmosphere-Rebuild-Time: 2024-06-26T17:38:39Z
 
-FROM ghcr.io/vexxhost/openstack-venv-builder:2023.1@sha256:c87a72a97266bf8518bac92f52abd6a054f5d99afff07d8c6e75c8033905679d AS build
+FROM ghcr.io/vexxhost/openstack-venv-builder:2023.1@sha256:21f33963f43a2cfbb46a7136666c6d86347cde612f1fb475be41719a2065dccc AS build
 RUN <<EOF bash -xe
 uv pip install \
     --constraint /upper-constraints.txt \