Remove the windows CI.

Author: LaurentMazare

.github/workflows/rust-ci.yml

@@ -8,7 +8,7 @@ jobs:
     runs-on: ${{ matrix.os }}
     strategy:
       matrix:
-        os: [ubuntu-latest, windows-2019, macOS-latest]
+        os: [ubuntu-latest, macOS-latest]
         rust: [stable, nightly]
     steps:
       - uses: actions/checkout@v2