chore: added new gh workflow for improving OSS gateway testing.

At the moment, we only rely on kong/kong image
for testing for OSS gateway. We have found cases
where users use kong/kong-gateway image, without
a license, to use as an OSS. To deal with these
scenarios and ensure deck works seemlessly with
them, we are adding this new workflow which uses
the EE image but has no license.

.github/workflows/integration-ee-image-no-license.yaml

@@ -0,0 +1,57 @@
+name: Integration Test (EE Image, No License)
+
+concurrency:
+  # Run only for most recent commit in PRs but for all tags and commits on main
+  # Ref: https://docs.github.com/en/actions/using-jobs/using-concurrency
+  group: ${{ github.workflow }}-${{ github.head_ref || github.sha }}
+  cancel-in-progress: true
+
+on:
+  push:
+    branches:
+    - main
+  pull_request: {}
+
+jobs:
+  integration:
+    timeout-minutes: ${{ fromJSON(vars.GHA_DEFAULT_TIMEOUT) }}
+    strategy:
+      matrix:
+        kong_image:
+        - 'kong/kong-gateway:2.8'
+        - 'kong/kong-gateway:3.4'
+        - 'kong/kong-gateway:3.5'
+        - 'kong/kong-gateway:3.6'
+        - 'kong/kong-gateway:3.7'
+        - 'kong/kong-gateway:3.8'
+        - 'kong/kong-gateway:3.9'
+        - 'kong/kong-gateway-dev:latest'
+    env:
+      KONG_ANONYMOUS_REPORTS: "off"
+      KONG_IMAGE: ${{ matrix.kong_image }}
+
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@v4
+      - name: Setup go
+        uses: actions/setup-go@v5
+        with:
+          go-version-file: go.mod
+      - name: Login to Docker Hub
+        uses: docker/login-action@v3
+        with:
+          username: ${{secrets.DOCKERHUB_PULL_USERNAME}}
+          password: ${{secrets.DOCKERHUB_PULL_TOKEN}}
+      - name: Setup Kong
+        env:
+        # adding blank license here
+        # we are deliberately checking an ee image against no license
+        # to check for errors when users use it as an OSS alternative
+          KONG_LICENSE_DATA: ""
+        run: make setup-kong-ee
+      - name: Run integration tests
+        env:
+          KONG_LICENSE_DATA: ${{ steps.license.outputs.license }}
+        run: make test-integration
+        continue-on-error: ${{ matrix.kong_image == 'kong/kong-gateway-dev:latest' }}