message: Use ubuntu-20.04 instead of ubuntu-latest
  ubuntu-latest is now ubuntu-22.04:
diff: @@ -8,7 +8,7 @@ jobs:
  linux-build-test:
  name: "test-${{ matrix.compiler }} Linux"
  - runs-on: ubuntu-latest
  + runs-on: ubuntu-20.04
  defaults:
  run:
  shell: bash
  @@ -92,7 +92,7 @@ jobs:
  linux-regression:
  name: "Regression ${{ matrix.compiler }} ${{matrix.shard}} (Linux)"
  - runs-on: ubuntu-latest
  + runs-on: ubuntu-20.04
  defaults:
  run:
  shell: bash
  @@ -195,7 +195,7 @@ jobs:
  linux-various:
  name: "${{ matrix.mode }} Linux"
  - runs-on: ubuntu-latest
  + runs-on: ubuntu-20.04
  defaults:
  run:
  shell: bash
  @@ -306,7 +306,7 @@ jobs:
  linux-valgrind:
  name: "Valgrind ${{ matrix.project}} (Linux)"
  - runs-on: ubuntu-latest
  + runs-on: ubuntu-20.04
  defaults:
  run:
  shell: bash
  