Add GHA to run MCS conformance tests

The GHA clones the "sigs.k8s.io/mcs-api" repo with the desired commit
and runs `go test` directly in the directory. "v0.1.0"  doesn't have
the conformance tests so we can't run them via Go import and trying to
import a later commit is problematic due  incompatible changes to the
MCS APIs. Also the conformance tests are really tied to the MCS spec
and not specifically to the API version so they'll likely evolve
separately anyway.

The clusterset IP field in the ServiceImport is required by the
spec for ClusterIP services so that conformance test will fail unless
the clusterset IP feature is enabled in Lighthouse. However, with
that enabled, the connectivity conformance tests will fail b/c Submariner
doesn't perform routing in that case. Thus, two separate GHA jobs are
configured, one with clusterset IP enabled and one without, and the
appropriate conformance tests are run/skipped by specifying the
appropriate Ginkgo label filter.

Signed-off-by: Tom Pantelis <[email protected]>

.github/workflows/e2e.yml

@@ -68,3 +68,49 @@ jobs:
       - name: Post mortem
         if: failure()
         uses: submariner-io/shipyard/gh-actions/post-mortem@devel
+  conformance-test:
+    name: MCS Conformance
+    needs: images
+    timeout-minutes: 60
+    runs-on: ubuntu-latest
+    strategy:
+      fail-fast: false
+      matrix:
+        using: ['clusterset-ip', '']
+    steps:
+      - name: Check out the repository
+        uses: actions/checkout@692973e3d937129bcbf40652eb9f2f61becf3332
+
+      - name: Check out the mcs-api repository
+        uses: actions/checkout@692973e3d937129bcbf40652eb9f2f61becf3332
+        with:
+          ref: 2b1ebf0d1a12261b9982393a5b0e4abceefa437f
+          repository: kubernetes-sigs/mcs-api
+          path: mcs-api
+
+      - name: Deploy Submariner
+        shell: bash
+        run: |
+          make deploy using="${{ matrix.using }}"
+
+      - name: Run conformance tests
+        shell: bash
+        run: |
+          export KUBECONFIG=$(find $(git rev-parse --show-toplevel)/output/kubeconfigs/ -type f -printf %p:)
+          label_filter="!ClusterIP || Connectivity"
+          if [[ "${{ matrix.using }}" =~ "clusterset-ip" ]]; then
+                label_filter="ClusterIP && !Connectivity"
+          fi
+          cd mcs-api/conformance
+          go test -v -timeout 30m -contexts cluster1,cluster2 -args -test.timeout 15m \
+              --ginkgo.v --ginkgo.trace --ginkgo.label-filter "${label_filter}"
+
+      - name: Print report.html
+        if: always()
+        shell: bash
+        run: |
+          cat mcs-api/conformance/report.html
+
+      - name: Post mortem
+        if: failure()
+        uses: submariner-io/shipyard/gh-actions/post-mortem@devel