Update image to bullseye from buster

Change-Id: Ie0a939e587a6c08d7fb9149cebb2b25425788823
diff --git a/nodepool/nodepool.yaml b/nodepool/nodepool.yaml
index beca1bc..f7dddb3 100644
--- a/nodepool/nodepool.yaml
+++ b/nodepool/nodepool.yaml
@@ -14,9 +14,9 @@
     zone: us-central1-a
     boot-timeout: 120
     cloud-images:
-      - name: debian-buster
+      - name: debian-bullseye
         image-project: debian-cloud
-        image-family: debian-10
+        image-family: debian-11
         username: zuul
         key: ssh-rsa AAAAB3NzaC1yc2EAAAADAQABAAABAQDaTT3+Y6dIh221ZsQ0ki6VwGb6lzd1/CvIS8RX6ZNmxJTXS7UKlvhAVTbGQPtmjdIQbwUyEqZEvIm/bUBr7dNbyeMLiRiRtoN+u1Quq8OAes2N7nUKnjLjGjVnM2mvYHGWHRDbpAQCtmXtbiQkHkfLLzewb+MqntQZ57xap31qriTkv4rdnlMN4kElILb5E/8WOAAJXYrt3b1TrTXwZUx7is1OTa38I9jJTpUMCn2otWGH9LlfeUhz/z8ZPB21wgUZN9CF5NwwBanqCNXy0jHiumOGx9e7Hc7apt641KiDuRt0aWyE6No/aMe6hVYnFR3NMG3rBtortXl+R5birK8l zuul
     pools:
@@ -36,59 +36,59 @@
         # long enough that it will have been updated by then).
         host-key-checking: False
         labels:
-          - name: debian-buster-8G
+          - name: debian-bullseye-8G
             instance-type: n1-standard-2
-            cloud-image: debian-buster
+            cloud-image: debian-bullseye
             volume-size: 40
-          - name: debian-buster-30G
+          - name: debian-bullseye-30G
             instance-type: n1-standard-8
-            cloud-image: debian-buster
+            cloud-image: debian-bullseye
             volume-size: 40
-          - name: debian-buster-60G
+          - name: debian-bullseye-60G
             instance-type: n1-standard-16
-            cloud-image: debian-buster
+            cloud-image: debian-bullseye
             volume-size: 40
-          - name: debian-buster-n1-standard-2
+          - name: debian-bullseye-n1-standard-2
             instance-type: n1-standard-2
-            cloud-image: debian-buster
+            cloud-image: debian-bullseye
             volume-size: 40
-          - name: debian-buster-n1-standard-8
+          - name: debian-bullseye-n1-standard-8
             instance-type: n1-standard-8
-            cloud-image: debian-buster
+            cloud-image: debian-bullseye
             volume-size: 40
-          - name: debian-buster-n1-standard-16
+          - name: debian-bullseye-n1-standard-16
             instance-type: n1-standard-16
-            cloud-image: debian-buster
+            cloud-image: debian-bullseye
             volume-size: 40
-          - name: debian-buster-e2-standard-2
+          - name: debian-bullseye-e2-standard-2
             instance-type: e2-standard-2
-            cloud-image: debian-buster
+            cloud-image: debian-bullseye
             volume-size: 40
-          - name: debian-buster-e2-standard-8
+          - name: debian-bullseye-e2-standard-8
             instance-type: e2-standard-8
-            cloud-image: debian-buster
+            cloud-image: debian-bullseye
             volume-size: 40
-          - name: debian-buster-e2-standard-16
+          - name: debian-bullseye-e2-standard-16
             instance-type: e2-standard-16
-            cloud-image: debian-buster
+            cloud-image: debian-bullseye
             volume-size: 40
 
 labels:
-  - name: debian-buster-8G
+  - name: debian-bullseye-8G
     min-ready: 0
-  - name: debian-buster-30G
+  - name: debian-bullseye-30G
     min-ready: 0
-  - name: debian-buster-60G
+  - name: debian-bullseye-60G
     min-ready: 0
-  - name: debian-buster-n1-standard-2
+  - name: debian-bullseye-n1-standard-2
     min-ready: 0
-  - name: debian-buster-n1-standard-8
+  - name: debian-bullseye-n1-standard-8
     min-ready: 0
-  - name: debian-buster-n1-standard-16
+  - name: debian-bullseye-n1-standard-16
     min-ready: 0
-  - name: debian-buster-e2-standard-2
+  - name: debian-bullseye-e2-standard-2
     min-ready: 0
-  - name: debian-buster-e2-standard-8
+  - name: debian-bullseye-e2-standard-8
     min-ready: 0
-  - name: debian-buster-e2-standard-16
+  - name: debian-bullseye-e2-standard-16
     min-ready: 0