message: ci: update release build OS to ubuntu 20.04
  Due to the deprecation of Ubuntu 18.04 as a runner target this PR updates the OS to 20.04 (see https://github.com/actions/runner-images/issues/6002), the next supported version of Ubuntu.
diff: @@ -27,39 +27,39 @@ jobs:
  # ======= Supported targets =======
  # Linux (x64, x86, aarch64)
  - {
  - os: "ubuntu-18.04",
  + os: "ubuntu-20.04",
  target: "x86_64-unknown-linux-gnu",
  cross: false,
  }
  - {
  - os: "ubuntu-18.04",
  + os: "ubuntu-20.04",
  target: "x86_64-unknown-linux-gnu",
  cross: false,
  container: quay.io/pypa/manylinux2014_x86_64,
  suffix: "2-17",
  }
  - {
  - os: "ubuntu-18.04",
  + os: "ubuntu-20.04",
  target: "i686-unknown-linux-gnu",
  cross: true,
  }
  - {
  - os: "ubuntu-18.04",
  + os: "ubuntu-20.04",
  target: "x86_64-unknown-linux-musl",
  cross: false,
  }
  - {
  - os: "ubuntu-18.04",
  + os: "ubuntu-20.04",
  target: "i686-unknown-linux-musl",
  cross: true,
  }
  - {
  - os: "ubuntu-18.04",
  + os: "ubuntu-20.04",
  target: "aarch64-unknown-linux-gnu",
  cross: true,
  }
  - {
  - os: "ubuntu-18.04",
  + os: "ubuntu-20.04",
  target: "aarch64-unknown-linux-musl",
  cross: true,
  }
  @@ -83,26 +83,26 @@ jobs:
  # ======= Unsupported targets =======
  # armv7
  - {
  - os: "ubuntu-18.04",
  + os: "ubuntu-20.04",
  target: "armv7-unknown-linux-gnueabihf",
  cross: true,
  }
  - {
  - os: "ubuntu-18.04",
  + os: "ubuntu-20.04",
  target: "armv7-unknown-linux-musleabihf",
  cross: true,
  }
  # PowerPC 64 LE
  - {
  - os: "ubuntu-18.04",
  + os: "ubuntu-20.04",
  target: "powerpc64le-unknown-linux-gnu",
  cross: true,
  }
  # Risc-V 64gc
  - {
  - os: "ubuntu-18.04",
  + os: "ubuntu-20.04",
  target: "riscv64gc-unknown-linux-gnu",
  cross: true,
  }
  @@ -241,7 +241,7 @@ jobs:
  build-deb:
  name: "Build Debian installers"
  - runs-on: "ubuntu-18.04"
  + runs-on: "ubuntu-20.04"
  strategy:
  fail-fast: false
  matrix:
  