message: [ci] remove ubuntu-18.04
diff: @@ -13,7 +13,7 @@ jobs:
  strategy:
  fail-fast: false
  matrix:
  - os: [ubuntu-18.04, ubuntu-latest, windows-latest, macOS-latest]
  + os: [ubuntu-latest, windows-latest, macOS-latest]
  board_version: [v3.6-56V]
  debug: [true]
  