Fix env var name

Author: marcleblanc2

base/frontend/sourcegraph-frontend.Deployment.yaml

@@ -104,7 +104,7 @@ spec:
               fieldPath: status.hostIP
         - name: OTEL_EXPORTER_OTLP_ENDPOINT
           value: http://$(OTEL_AGENT_HOST):4317
-        - name: DEPLOY
+        - name: DEPLOY_TYPE
           value: "LegacyKustomize"
         terminationMessagePolicy: FallbackToLogsOnError
         livenessProbe: