Read
https://stackoverflow.com/questions/39709941/jenkins-not-able-to-access-internet-when-running-as-docker-container

docker-compose.yml
version: "2.3"
services: 
  jenkins:
    container_name: jenkins
    image: jenkins/jenkins:lts-jdk11
    restart: unless-stopped
    ports: 
      - "8080:8080"
      - "50000:50000"
    volumes: 
      - "/home/pi/Docker/jenkins:/var/jenkins_home"
    dns:
      - 8.8.8.8
      - 4.4.4.4