stuck on "starting your workflow run" on Github Actions

I wanted to test "github action" feature but it is not starting and its is stuck.It just says "Starting your workflow run..." Is there something wrong in my build.yml file

This is my build.yml file:

name: CI

on:
  pull_request:
    branches:
      - master

  workflow_dispatch:

env:
  POSTGRESQL_VERSION: 13.1
  POSTGRESQL_DB: students_info
  POSTGRESQL_USER: postgres
  POSTGRESQL_PASSWORD: password
  JAVA_VERSION: 1.15

jobs:
  build:
    runs-on: ubuntu-16.04
    services:
      postgres:
        image: postgres:13.1
        env:
          POSTGRES_DB: ${{ env.POSTGRESQL_DB }}
          POSTGRES_USER: ${{ env.POSTGRESQL_USER }}
          POSTGRES_PASSWORD: ${{ env.POSTGRESQL_PASSWORD }}
        ports:
          - 5432:5432
        options: --health-cmd pg_isready --health-interval 10s --health-timeout 5s --health-retries 5
    steps:
      - uses: actions/checkout@v2
      - uses: actions/setup-java@v1.4.3
        with:
          java-version: ${{ env.JAVA_VERSION }}
      - name: Maven Clean Package
        run: |
          ./mvnw --no-transfer-progress clean package -P build-frontend

PS:I have tried with ubuntu-latest as well