ci: Temporarily bypoass the pipeline issue

On Ubuntu 24.04 the default apparmor profile restricts unprivileged user
namespaces. This breaks the bitbake execution, as bitbake uses this
mechanism for network and uid isolation, resulting in the following
error message:

 File "/work/isar/bitbake/bin/bitbake-worker", line 268, in child
     bb.utils.disable_network(uid, gid)
   File "/work/isar/bitbake/lib/bb/utils.py", line 1653, in
disable_network
     with open("/proc/self/uid_map", "w") as f:
 PermissionError: [Errno 1] Operation not permitted

Upgrading kas to version 4.7 will resolve this issue completely in the
future.

Signed-off-by: Li Hua Qian <[email protected]>

.github/workflows/main.yml

@@ -9,7 +9,7 @@ concurrency:
 jobs:
   debian-example-image:
     name: Debian example image
-    runs-on: ubuntu-latest
+    runs-on: ubuntu-22.04
     steps:
       - name: Checkout
         uses: actions/checkout@v4
@@ -27,7 +27,7 @@ jobs:
 
   debian-swupdate-image:
     name: Debian secure boot SWUpdate image
-    runs-on: ubuntu-latest
+    runs-on: ubuntu-22.04
     steps:
       - name: Checkout
         uses: actions/checkout@v4
@@ -50,7 +50,7 @@ jobs:
 
   bootloaders:
     name: Bootloaders
-    runs-on: ubuntu-latest
+    runs-on: ubuntu-22.04
     steps:
       - name: Checkout
         uses: actions/checkout@v4