test(e2e-runner): install oasdiff before unit tests

Author: jakebromberg

.github/workflows/e2e-runner-smoke.yml

@@ -14,6 +14,11 @@ jobs:
           echo "== docker =="; docker --version
           echo "== python =="; python3.12 --version
           echo "== uname =="; uname -a
+      - uses: actions/setup-go@v5
+        with:
+          go-version: '1.22'
+      - name: Install oasdiff
+        run: GOBIN=/usr/local/bin sudo -E env "PATH=$PATH" go install github.com/oasdiff/oasdiff@latest
       - name: npm ci
         run: npm ci --ignore-scripts
       - name: unit tests