[Actions] Separate darwin builds

Author: ttiimm

.github/workflows/rust.yml

@@ -17,8 +17,9 @@ jobs:
     runs-on: ${{ matrix.os }}
     timeout-minutes: 30
     strategy:
+      # ensures each build runs even if one fails
+      fail-fast: false
       matrix:
-        os: [ubuntu-latest, macos-latest, windows-latest]
         include:
           - os: ubuntu-latest
             target: x86_64-unknown-linux-gnu