Update windows workflow to use environment files (#83)

Author: shabalind

.github/workflows/tests_windows.yaml

@@ -10,20 +10,23 @@ jobs:
     - name: Install swift-DEVELOPMENT-SNAPSHOT-2020-09-22-a
       run: |
         Install-Binary -Url "https://swift.org/builds/development/windows10/swift-DEVELOPMENT-SNAPSHOT-2020-09-22-a/swift-DEVELOPMENT-SNAPSHOT-2020-09-22-a-windows10.exe" -Name "installer.exe" -ArgumentList ("-q")
+
     - name: Set Environment Variables
       run: |
-        echo "::set-env name=SDKROOT::C:\Library\Developer\Platforms\Windows.platform\Developer\SDKs\Windows.sdk"
-        echo "::set-env name=DEVELOPER_DIR::C:\Library\Developer"
+        echo "SDKROOT=C:\Library\Developer\Platforms\Windows.platform\Developer\SDKs\Windows.sdk" | Out-File -FilePath $env:GITHUB_ENV -Encoding utf8 -Append
+        echo "DEVELOPER_DIR=C:\Library\Developer" | Out-File -FilePath $env:GITHUB_ENV -Encoding utf8 -Append
+
     - name: Adjust Paths
       run: |
-        echo "::add-path::C:\Library\Developer\Toolchains\unknown-Asserts-development.xctoolchain\usr\bin;C:\Library\Swift-development\bin;C:\Library\icu-67\usr\bin"
+        echo "C:\Library\Developer\Toolchains\unknown-Asserts-development.xctoolchain\usr\bin" | Out-File -FilePath $env:GITHUB_PATH -Encoding utf8 -Append
+        echo "C:\Library\Swift-development\bin;C:\Library\icu-67\usr\bin" | Out-File -FilePath $env:GITHUB_PATH -Encoding utf8 -Append
+
     - name: Install Supporting Files
-      shell: cmd
       run: |
-        copy "%SDKROOT%\usr\share\ucrt.modulemap" "%UniversalCRTSdkDir%\Include\%UCRTVersion%\ucrt\module.modulemap"
-        copy "%SDKROOT%\usr\share\visualc.modulemap" "%VCToolsInstallDir%\include\module.modulemap"
-        copy "%SDKROOT%\usr\share\visualc.apinotes" "%VCToolsInstallDir%\include\visualc.apinotes"
-        copy "%SDKROOT%\usr\share\winsdk.modulemap" "%UniversalCRTSdkDir%\Include\%UCRTVersion%\um\module.modulemap"
+        Copy-Item "$env:SDKROOT\usr\share\ucrt.modulemap" -destination "$env:UniversalCRTSdkDir\Include\$env:UCRTVersion\ucrt\module.modulemap"
+        Copy-Item "$env:SDKROOT\usr\share\visualc.modulemap" -destination "$env:VCToolsInstallDir\include\module.modulemap"
+        Copy-Item "$env:SDKROOT\usr\share\visualc.apinotes" -destination "$env:VCToolsInstallDir\include\visualc.apinotes"
+        Copy-Item "$env:SDKROOT\usr\share\winsdk.modulemap" -destination "$env:UniversalCRTSdkDir\Include\$env:UCRTVersion\um\module.modulemap"
 
     - name: Swift version
       run: swift --version