Distribute prebuilt binary for x86_64 illumos (#252)

Author: zeeshanlakhani

.github/workflows/release.yml

@@ -49,6 +49,7 @@ jobs:
           - target: x86_64-pc-windows-msvc
             os: windows-2019
           - target: x86_64-unknown-freebsd
+          - target: x86_64-unknown-illumos
           - target: universal-apple-darwin
             os: macos-12
     runs-on: ${{ matrix.os || 'ubuntu-20.04' }}