fix(conformance): Use pinned version of EPP for conformance test instead of main. (#1262)

* Use pinned version of EPP for conformance test instead of main.

* update pinned version.

Author: zetxqx

conformance/resources/base.yaml

@@ -200,7 +200,7 @@ spec:
       terminationGracePeriodSeconds: 130
       containers:
       - name: epp
-        image: us-central1-docker.pkg.dev/k8s-staging-images/gateway-api-inference-extension/epp:main
+        image: us-central1-docker.pkg.dev/k8s-staging-images/gateway-api-inference-extension/epp:v1.0.0
         imagePullPolicy: Always
         args:
         - --pool-name
@@ -298,7 +298,7 @@ spec:
       terminationGracePeriodSeconds: 130
       containers:
       - name: epp
-        image: us-central1-docker.pkg.dev/k8s-staging-images/gateway-api-inference-extension/epp:main
+        image: us-central1-docker.pkg.dev/k8s-staging-images/gateway-api-inference-extension/epp:v1.0.0
         imagePullPolicy: Always
         args:
         - --pool-name