ci: Run integration tests on Alpine

This way we are making sure that the integration tests infra doesn't
regress on musl environments.

.github/workflows/ci.yml

@@ -202,19 +202,25 @@ jobs:
           - target: x86_64-unknown-linux-gnu
             # We don't use ubuntu-latest because we care about the apt packages available.
             os: ubuntu-22.04
+          - target: x86_64-unknown-linux-musl
+            os: ubuntu-22.04
+            container: ghcr.io/vadorovsky/gh-act-containers/alpine:moar-packages-3.20
     runs-on: ${{ matrix.os }}
+    container: ${{ matrix.container }}
     steps:
       - uses: actions/checkout@v4
         with:
           submodules: recursive
 
       - name: Install prerequisites
-        if: runner.os == 'Linux'
+        if: runner.os == 'Linux' && matrix.container == ''
         # ubuntu-22.04 comes with clang 13-15[0]; support for signed and 64bit
         # enum values was added in clang 15[1] which isn't in `$PATH`.
         #
         # gcc-multilib provides at least <asm/types.h> which is referenced by libbpf.
         #
+        # QEMU is used to run virtualized integration tests.
+        #
         # [0] https://github.com/actions/runner-images/blob/main/images/ubuntu/Ubuntu2204-Readme.md
         #
         # [1] https://github.com/llvm/llvm-project/commit/dc1c43d
@@ -224,6 +230,19 @@ jobs:
           sudo apt -y install gcc-multilib lynx qemu-system-{arm,x86}
           echo /usr/lib/llvm-15/bin >> $GITHUB_PATH
 
+      - name: Install prerequisites
+        if: runner.os == 'Linux' && contains(matrix.container, 'alpine')
+        # dpkg is used to unpack the kernel images from .deb packages, which we
+        # use for virtualized tests.
+        #
+        # QEMU is used to run virtualized integration tests.
+        run: |
+          set -euxo pipefail
+          apk add \
+            dpkg \
+            qemu-system-arm \
+            qemu-system-x86_64
+
       - name: Install prerequisites
         if: runner.os == 'macOS'
         # The xargs shipped on macOS always exits 0 with -P0, so we need GNU findutils.