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.

Signed-off-by: Tom Pantelis <tompantelis@gmail.com>

.github/workflows/e2e.yml

@@ -68,3 +68,34 @@ jobs:
       - name: Post mortem
         if: failure()
         uses: submariner-io/shipyard/gh-actions/post-mortem@devel
+  conformance-test:
+    name: MCS Conformance
+    needs: images
+    timeout-minutes: 30
+    runs-on: ubuntu-latest
+    steps:
+      - name: Check out the repository
+        uses: actions/checkout@692973e3d937129bcbf40652eb9f2f61becf3332
+
+      - name: Check out the mcs-api repository
+        uses: actions/checkout@692973e3d937129bcbf40652eb9f2f61becf3332
+        with:
+          ref: b63b16d83943d70728e98ca438b83741cdeddb9b
+          repository: tpantelis/mcs-api
+          path: mcs-api
+
+      - name: Deploy Submariner
+        shell: bash
+        run: |
+          make deploy
+
+      - name: Run conformance tests
+        shell: bash
+        run: |
+          export KUBECONFIG=$(find $(git rev-parse --show-toplevel)/output/kubeconfigs/ -type f -printf %p:)
+          cd mcs-api/conformance
+          go test -v -timeout 30m -contexts cluster1,cluster2 -args -test.timeout 15m --ginkgo.v --ginkgo.trace
+
+      - name: Post mortem
+        if: failure()
+        uses: submariner-io/shipyard/gh-actions/post-mortem@devel