message: Add build matrix for `PLATFORM` env var
  Set `fail-fast` to `false`, so a failed build won't immediately
  terminate other parallel jobs that are in progress. That means we can
  still see the result of other builds, either pass or fail, despite
  having already seen a failure.
diff: @@ -13,7 +13,13 @@ env:
  jobs:
  build:
  + strategy:
  + fail-fast: false
  + matrix:
  + platform: [x86, x64]
  runs-on: windows-latest
  + env:
  + PLATFORM: ${{ matrix.platform }}
  steps:
  - uses: actions/checkout@v2
  