Minor cleanup to GitHub Actions Windows build.

.github/workflows/main.yml

@@ -37,6 +37,7 @@ jobs:
         path: love-${{ github.sha }}.AppImage
   windows-os:
     runs-on: windows-latest
+    shell: cmd
     strategy:
       matrix:
         platform: [Win32, x64]
@@ -50,7 +51,6 @@ jobs:
         - install: compat
           compatdef: -DLOVE_INSTALL_UCRT=ON
           compatname: -compat
-
     steps:
     - name: Clone Megasource
       uses: actions/checkout@v2
@@ -69,12 +69,10 @@ jobs:
         vulkan-components: Vulkan-Headers, Vulkan-Loader
         vulkan-use-cache: true
     - name: Configure
-      shell: cmd
       env:
         PLATFORM: ${{ matrix.platform }}
       run: cmake -Bbuild -Hmegasource -T v142 -A %PLATFORM% ${{ matrix.compatdef }} -DCMAKE_INSTALL_PREFIX=%CD%\install
     - name: Install
-      shell: cmd
       run: cmake --build build --target PACKAGE --config Release -j2
     - name: Artifact
       uses: actions/upload-artifact@v2