Fixes CI docker tag for Isaac Sim (isaac-sim#496)

Fixes Isaac Sim docker tag

## Type of change

- Bug fix (non-breaking change which fixes an issue)

.github/workflows/postmerge-ci-buildspec.yml

@@ -5,7 +5,7 @@ phases:
     commands:
       - echo "Building a docker image"
       - docker login -u \$oauthtoken -p $NGC_TOKEN nvcr.io
-      - docker build -t $IMAGE_NAME:latest-1.0 --build-arg ISAACSIM_VERSION_ARG=latest-4.0 --build-arg ISAACSIM_ROOT_PATH_ARG=/isaac-sim --build-arg ISAACLAB_PATH_ARG=/workspace/isaaclab --build-arg DOCKER_USER_HOME_ARG=/root -f docker/Dockerfile.base .
+      - docker build -t $IMAGE_NAME:latest-1.0 --build-arg ISAACSIM_VERSION_ARG=4.0.0 --build-arg ISAACSIM_ROOT_PATH_ARG=/isaac-sim --build-arg ISAACLAB_PATH_ARG=/workspace/isaaclab --build-arg DOCKER_USER_HOME_ARG=/root -f docker/Dockerfile.base .
       - echo "Pushing the docker image"
       - docker push $IMAGE_NAME:latest-1.0
       - docker tag $IMAGE_NAME:latest-1.0 $IMAGE_NAME:latest-1.0-b$CODEBUILD_BUILD_NUMBER