CI: Always use Command Prompt when running commands.

.github/workflows/deps-test.yml

@@ -8,6 +8,9 @@ jobs:
       fail-fast: false
       matrix:
         platform: [Win32, x64]
+    defaults:
+      run:
+        shell: cmd
     steps:
     - name: Checkout
       uses: actions/checkout@v2
@@ -24,10 +27,8 @@ jobs:
         move /y C:\Strawberry C:\Strawberry_not_in_PATH
         exit /b 0
     - name: Configure
-      shell: cmd
       env:
         PLATFORM: ${{ matrix.platform }}
       run: cmake -Bbuild -Hmegasource -T v142 -A %PLATFORM% -DCMAKE_INSTALL_PREFIX=%CD%\install
     - name: Install
-      shell: cmd
       run: cmake --build build --config Release --target install -j2