Install .NET 9 SDK in CI script

Author: Sergio0694

appveyor.yml

@@ -23,6 +23,7 @@
     - ps: '& "$($env:DOTNET_INSTALL_DIR)/dotnet-install.ps1" -Channel 6.0 -InstallDir $env:DOTNET_INSTALL_DIR'
     - ps: '& "$($env:DOTNET_INSTALL_DIR)/dotnet-install.ps1" -Channel 7.0 -InstallDir $env:DOTNET_INSTALL_DIR'
     - ps: '& "$($env:DOTNET_INSTALL_DIR)/dotnet-install.ps1" -Channel 8.0 -InstallDir $env:DOTNET_INSTALL_DIR'
+    - ps: '& "$($env:DOTNET_INSTALL_DIR)/dotnet-install.ps1" -Channel 9.0 -InstallDir $env:DOTNET_INSTALL_DIR'
     - ps: $env:Path = "$env:DOTNET_INSTALL_DIR;$env:Path"
     - ps: dotnet --info
 
@@ -67,6 +68,7 @@
     - ps: '& "$($env:DOTNET_INSTALL_DIR)/dotnet-install.ps1" -Channel 6.0 -InstallDir $env:DOTNET_INSTALL_DIR'
     - ps: '& "$($env:DOTNET_INSTALL_DIR)/dotnet-install.ps1" -Channel 7.0 -InstallDir $env:DOTNET_INSTALL_DIR'
     - ps: '& "$($env:DOTNET_INSTALL_DIR)/dotnet-install.ps1" -Channel 8.0 -InstallDir $env:DOTNET_INSTALL_DIR'
+    - ps: '& "$($env:DOTNET_INSTALL_DIR)/dotnet-install.ps1" -Channel 9.0 -InstallDir $env:DOTNET_INSTALL_DIR'
     - ps: $env:Path = "$env:DOTNET_INSTALL_DIR;$env:Path"
     - ps: dotnet --info