[FlINK-36392] export the var

Author: SamBarker

.github/workflows/ci.yml

@@ -166,8 +166,8 @@ jobs:
           export SHELL=/bin/bash
           export DOCKER_BUILDKIT=1
           eval $(minikube -p minikube docker-env)
-          JAVA_VERSION=${{ matrix.java-version }}
-          docker build --progress=plain --no-cache -f ./Dockerfile -t flink-kubernetes-operator:ci-latest --progress --build-arg JAVA_VERSION="${JAVA_VERSION:-11}" plain -- .
+          export JAVA_VERSION=${{ matrix.java-version }}
+          docker build --progress=plain --no-cache -f ./Dockerfile -t flink-kubernetes-operator:ci-latest --progress --build-arg JAVA_VERSION="${JAVA_VERSION:-11}" plain .
           docker images
       - name: Start the operator
         run: |