csproj: update to .NET 4.8

GitHub: #2

Signed-off-by: Lev Stipakov <[email protected]>

Author: lstipakov

OpenVpnService.csproj

@@ -10,7 +10,7 @@
     <AppDesignerFolder>Properties</AppDesignerFolder>
     <RootNamespace>OpenVpnService</RootNamespace>
     <AssemblyName>OpenVpnServ2</AssemblyName>
-    <TargetFrameworkVersion>v4.0</TargetFrameworkVersion>
+    <TargetFrameworkVersion>v4.8</TargetFrameworkVersion>
     <TargetFrameworkProfile>
     </TargetFrameworkProfile>
     <FileAlignment>512</FileAlignment>