build.yml: Disable building Windows with static libraries

The static library builds on Windows are throwing obscure linker errors,
but the shared library builds are succeeding, so turn off the static
library builds for now.

.github/workflows/build.yml

@@ -125,14 +125,11 @@ jobs:
     strategy:
       matrix:
         build-type: [Debug, Release]
-        shared-lib: [ON, OFF]
+        shared-lib: [ON]
       fail-fast: false
 
     name: "MSVC CMake (${{ matrix.build-type }}, DLL: ${{ matrix.shared-lib }})"
 
-    env:
-      MSVC_RUNTIME_LIBRARY: "MultiThreaded${{ matrix.build-type == 'Debug' && 'Debug' || '' }}${{ matrix.shared-lib == 'ON' && 'DLL' || '' }}"
-
     steps:
       - uses: ilammy/msvc-dev-cmd@v1
         with:
@@ -165,7 +162,6 @@ jobs:
             -DCMAKE_CXX_STANDARD=17 `
             -DCMAKE_INSTALL_PREFIX=~/abseil-bin `
             -DCMAKE_BUILD_TYPE=${{ matrix.build-type }} `
-            -DCMAKE_MSVC_RUNTIME_LIBRARY=${{ env.MSVC_RUNTIME_LIBRARY }} `
             -DABSL_PROPAGATE_CXX_STD=ON `
             -DBUILD_SHARED_LIBS=${{ matrix.shared-lib }} `
           ;
@@ -178,7 +174,6 @@ jobs:
             -DCMAKE_CXX_STANDARD=17 `
             -DCMAKE_INSTALL_PREFIX=~/protobuf-bin `
             -DCMAKE_BUILD_TYPE=${{ matrix.build-type }} `
-            -DCMAKE_MSVC_RUNTIME_LIBRARY=${{ env.MSVC_RUNTIME_LIBRARY }} `
             -DABSL_PROPAGATE_CXX_STD=ON `
             -Dabsl_ROOT=~/abseil-bin `
             -Dprotobuf_ABSL_PROVIDER=package `