Bump to stable/2026.1

- Dockerfile: openstack-venv-builder: main -> 2026.1
- Dockerfile: python-base: main -> 2026.1

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
Signed-off-by: Mohammed Naser <mnaser@vexxhost.com>

Author: mnaser

Dockerfile

@@ -2,7 +2,7 @@
 # SPDX-License-Identifier: GPL-3.0-or-later
 # Atmosphere-Rebuild-Time: 2024-06-25T22:49:25Z
 
-FROM ghcr.io/vexxhost/openstack-venv-builder:main@sha256:d47d2e2bf1498b2e4e36f5f645e41d995104d7d28ffa6ecadb96447f28b09680 AS build
+FROM ghcr.io/vexxhost/openstack-venv-builder:2026.1@sha256:4f3f182f9ecc0d4624f28f2b15064f92cfa33b8887d1a5acb85fdb9f4f9cc6c6 AS build
 RUN <<EOF bash -xe
 uv pip install \
     --constraint /upper-constraints.txt \
@@ -21,7 +21,7 @@ uv pip install \
         tap-as-a-service
 EOF
 
-FROM ghcr.io/vexxhost/python-base:main@sha256:95dce35dcbda1eaaa303ab47d76869728de278d64cbbdebd42b8de2330347751
+FROM ghcr.io/vexxhost/python-base:2026.1@sha256:a570b4c94c85b6359733def197eae3eb0f15818629c2d6b42a7cbb1a885325b5
 COPY --from=build --link /var/lib/openstack /var/lib/openstack
 
 # NOTE(mnaser): The Magnum client relies on the SHELL environment variable