public Builder setEnvironment(Map<String, String> environment) {
      this.environment = new HashMap<>(environment);
      return this;
    }
Sets the container environment. These environment variables are available to the program
launched by the container entrypoint command. This replaces any previously-set environment
variables. Note that these values are added to the base image values.

<p>This is similar to <a href="https://docs.docker.com/engine/reference/builder/#env">{@code
ENV} in Dockerfiles</a> or {@code env} in the <a
href="https://kubernetes.io/docs/reference/generated/kubernetes-api/v1.11/#container-v1-core">Kubernetes
Container spec</a>.

@param environment a map of environment variable names to values
@return this
jib-build-plan/src/main/java/com/google/cloud/tools/jib/api/buildplan/ContainerBuildPlan.java