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:c8e3b9b85b78bf65aa9d43653ce24600161b952b62460c53bca55f7212ceb739 AS build
+FROM ghcr.io/vexxhost/openstack-venv-builder:2026.1@sha256:4d8390ccb715010a3504200f47405318309c4ba48ac0010d2b2a0764a73cc7de 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