only run system lib step for windows

.github/workflows/installation_test.yml

@@ -37,13 +37,14 @@ jobs:
           restore-keys: ${{ runner.os }}-R-${{ matrix.r-version }}-
 
       - name: System Libraries
+        if: runner.os != 'Windows'
         run: |
-          if [ "${{ matrix.os }}" = "ubuntu-latest" ]; then
+          if [ "${{ matrix.os }}" == "ubuntu-latest" ]; then
             sudo apt-get update
             sudo apt-get install -y libfontconfig1-dev libudunits2-dev libcairo2-dev libcurl4-openssl-dev \
                                     libharfbuzz-dev libfribidi-dev libfreetype6-dev libpng-dev libtiff5-dev \
                                     libjpeg-dev libgdal-dev libgeos-dev libproj-dev
-          elif [ "${{ matrix.os }}" = "macOS-latest" ]; then
+          elif [ "${{ matrix.os }}" == "macOS-latest" ]; then
             brew install freetype udunits cairo harfbuzz fribidi libpng libtiff jpeg gdal pkg-config
           fi