switch.yml: Update CMake

.github/workflows/switch.yml

@@ -33,7 +33,11 @@ jobs:
 
       - name: Install dependencies
         run: |
-          apt-get update && \
+          tee /etc/apt/sources.list.d/bullseye-backports.list <<LIST
+          deb http://deb.debian.org/debian bullseye-backports main
+          LIST
+          apt-get update
+          apt-get install -y -t bullseye-backports cmake
           apt-get install -y --no-install-recommends --no-install-suggests \
             gettext