remove win32-msvc from build matrix as it fails due to permission-den…

…ied with rustup.exe

This seems like an odd problem to have and nothign to spend time on given
the lack of importance of the win32 platform. We would except open-rs
to build fine on win32 if it builds for win64.

.github/workflows/cross-platform-testing.yml

@@ -20,7 +20,7 @@ jobs:
       RUST_BACKTRACE: 1
     strategy:
       matrix:
-        build: [linux, linux-arm, macos, win-msvc, win-gnu, win32-msvc]
+        build: [linux, linux-arm, macos, win-msvc, win-gnu]
         include:
           - build: linux
             os: ubuntu-18.04
@@ -42,10 +42,6 @@ jobs:
             os: windows-2019
             rust: stable
             target: x86_64-pc-windows-gnu
-          - build: win32-msvc
-            os: windows-2019
-            rust: stable
-            target: i686-pc-windows-msvc
 
     steps:
       - name: Checkout repository