Update the accessbot image to bullseye

This is general spring cleaning that we are going to try and do for our
images now that bullseye is out.

Change-Id: Iad8f5b76896b88a6aafbfba0c38d0749b9d5c88f

docker/accessbot/Dockerfile

@@ -13,7 +13,7 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-FROM docker.io/opendevorg/python-base:3.7
+FROM docker.io/opendevorg/python-base:3.9-bullseye
 
 RUN pip install pyyaml irc
 COPY accessbot.py /usr/local/bin/accessbot.py

zuul.d/docker-images/accessbot.yaml

@@ -3,7 +3,7 @@
     name: system-config-build-image-accessbot
     description: Build a accessbot image.
     parent: system-config-build-image
-    requires: python-base-3.7-buster-container-image
+    requires: python-base-3.9-bullseye-container-image
     provides: accessbot-container-image
     vars: &accessbot_vars
       docker_images:
@@ -17,7 +17,7 @@
     name: system-config-upload-image-accessbot
     description: Build and upload a accessbot image.
     parent: system-config-upload-image
-    requires: python-base-3.7-buster-container-image
+    requires: python-base-3.9-bullseye-container-image
     provides: accessbot-container-image
     vars: *accessbot_vars
     files: *accessbot_files

zuul.d/project.yaml

@@ -133,7 +133,7 @@
         - system-config-build-image-accessbot:
             dependencies:
               - name: opendev-buildset-registry
-              - name: system-config-build-image-python-base-3.7-buster
+              - name: system-config-build-image-python-base-3.9-bullseye
                 soft: true
         - system-config-build-image-ircbot:
             dependencies:
@@ -283,7 +283,7 @@
         - system-config-upload-image-accessbot:
             dependencies:
               - name: opendev-buildset-registry
-              - name: system-config-upload-image-python-base-3.7-buster
+              - name: system-config-upload-image-python-base-3.9-bullseye
                 soft: true
         - system-config-upload-image-ircbot:
             dependencies: