Ensure MSVC toolset 14.15 is available

windows/Dockerfile

@@ -6,7 +6,7 @@ RUN [Net.ServicePointManager]::SecurityProtocol = [Net.SecurityProtocolType]::Tl
     Invoke-Expression ((New-Object Net.WebClient).DownloadString('https://chocolatey.org/install.ps1')); \
     choco install -y visualstudio2017buildtools; \
     choco install -y visualstudio2017-workload-vctools; \
-    Start-Process "\"C:/Program Files (x86)/Microsoft Visual Studio/Installer/vs_installer.exe\"" -NoNewWindow -Wait -ArgumentList 'modify --installPath \"C:/Program Files (x86)/Microsoft Visual Studio/2017/BuildTools\" --quiet --norestart --remove Microsoft.VisualStudio.Component.VC.CMake.Project --add Microsoft.VisualStudio.Component.VC.Tools.14.13 --add Microsoft.VisualStudio.Component.VC.ATL'; \
+    Start-Process "\"C:/Program Files (x86)/Microsoft Visual Studio/Installer/vs_installer.exe\"" -NoNewWindow -Wait -ArgumentList 'modify --installPath \"C:/Program Files (x86)/Microsoft Visual Studio/2017/BuildTools\" --quiet --norestart --remove Microsoft.VisualStudio.Component.VC.CMake.Project --add Microsoft.VisualStudio.Component.VC.Tools.14.13 --add Microsoft.VisualStudio.Component.VC.Tools.14.15 --add Microsoft.VisualStudio.Component.VC.ATL'; \
     choco install -y cmake --version 3.12.2 --installargs "ADD_CMAKE_TO_PATH=System"; \
     choco install -y \
         git \