[FlINK-36332] Variables don't need exported.

Author: SamBarker

.github/workflows/ci.yml

@@ -101,8 +101,9 @@ jobs:
           export SHELL=/bin/bash
           export DOCKER_BUILDKIT=1
           eval $(minikube -p minikube docker-env)
+          JAVA_VERSION=${{matrix.java-version}}
           HTTP_CLIENT=${{ matrix.http-client }}
-          docker build --progress=plain --no-cache -f ./Dockerfile -t flink-kubernetes-operator:ci-latest --progress plain --build-arg HTTP_CLIENT="${HTTP_CLIENT:-okhttp}" .
+          docker build --progress=plain --no-cache -f ./Dockerfile -t flink-kubernetes-operator:ci-latest --progress plain --build-arg JAVA_VERSION="${JAVA_VERSION:-11}" --build-arg HTTP_CLIENT="${HTTP_CLIENT:-okhttp}" .
           docker images
       - name: Start the operator
         run: |
@@ -230,7 +231,7 @@ jobs:
           export SHELL=/bin/bash
           export DOCKER_BUILDKIT=1
           eval $(minikube -p minikube docker-env)
-          export JAVA_VERSION=${{ matrix.java-version }}
+          JAVA_VERSION=${{ matrix.java-version }}
           docker build --progress=plain --no-cache -f ./Dockerfile -t flink-kubernetes-operator:ci-latest --progress plain --build-arg JAVA_VERSION="${JAVA_VERSION:-11}" .
           docker images
       - name: Start the operator