[WIP] CI: test on 32-bit and 64-bit Windows (GNU)

Author: tarcieri

.github/workflows/md5.yml

@@ -37,6 +37,26 @@ jobs:
             toolchain: stable
             deps: true
 
+          # 32-bit Windows (GNU)
+          - target: i686-pc-windows-gnu
+            platform: windows-latest
+            toolchain: 1.41.0 # MSRV
+            deps: true
+          - target: i686-pc-windows-gnu
+            platform: windows-latest
+            toolchain: stable
+            deps: true
+
+          # 64-bit Windows (GNU)
+          - target: x86_64-pc-windows-gnu
+            platform: windows-latest
+            toolchain: 1.41.0 # MSRV
+            deps: true
+          - target: x86_64-pc-windows-gnu
+            platform: windows-latest
+            toolchain: stable
+            deps: true
+
     runs-on: ${{ matrix.platform }}
     steps:
       - uses: actions/checkout@v1