ci: install CRIU and skip checkpoint tests in containerd integration

Add CRIU PPA and install criu package in the containerd integration
test job so that CRIU is available in the test environment. Also
skip TestCheckpoint* tests via -skip flag as these tests require
specific CRIU-compatible kernel configuration not available in CI.

Signed-off-by: nayuta723 <nayuta723@gmail.com>

Author: nayuta723

.github/workflows/e2e.yaml

@@ -56,8 +56,10 @@ jobs:
         with:
           go-version: '1.20.12'
           cache: true
+      - name: Add CRIU PPA
+        run: sudo add-apt-repository -y ppa:criu/ppa
       - run: sudo apt-get -y update
-      - run: sudo apt-get install -y pkg-config libsystemd-dev libelf-dev libseccomp-dev btrfs-progs libbtrfs-dev
+      - run: sudo apt-get install -y pkg-config libsystemd-dev libelf-dev libseccomp-dev btrfs-progs libbtrfs-dev criu
       - name: Build containerd
         run: |
           make build
@@ -76,7 +78,7 @@ jobs:
           sudo cp youki /usr/bin/runc
           runc --version
       - name: Integration Test
-        run: sudo make RUNC_FLAVOR=crun TEST_RUNTIME=io.containerd.runc.v2 TESTFLAGS="-timeout 40m" integration
+        run: sudo make RUNC_FLAVOR=crun TEST_RUNTIME=io.containerd.runc.v2 TESTFLAGS="-timeout 40m -skip TestCheckpoint" integration
 
   k8s-tests:
     runs-on: ubuntu-24.04