Use <TargetFrameworks> property in templates.

Author: timcassell

src/BenchmarkDotNet/Templates/CsProj.txt

@@ -4,7 +4,7 @@
     <ImportDirectoryBuildProps>false</ImportDirectoryBuildProps>
     <ImportDirectoryBuildTargets>false</ImportDirectoryBuildTargets>
     <AssemblyTitle>$PROGRAMNAME$</AssemblyTitle>
-    <TargetFramework>$TFM$</TargetFramework>
+    <TargetFrameworks>$TFM$</TargetFrameworks>
     <AllowUnsafeBlocks>true</AllowUnsafeBlocks>
     <PlatformTarget>$PLATFORM$</PlatformTarget>
     <AssemblyName>$PROGRAMNAME$</AssemblyName>

src/BenchmarkDotNet/Templates/MonoAOTLLVMCsProj.txt

@@ -9,7 +9,7 @@
 
   <PropertyGroup>
     <OutputType>Exe</OutputType>
-    <TargetFramework>$TFM$</TargetFramework>
+    <TargetFrameworks>$TFM$</TargetFrameworks>
     <MicrosoftNetCoreAppRuntimePackDir>$RUNTIMEPACK$</MicrosoftNetCoreAppRuntimePackDir>
     <RuntimeIdentifier>$RUNTIMEIDENTIFIER$</RuntimeIdentifier>
     <EnableTargetingPackDownload>false</EnableTargetingPackDownload>

src/BenchmarkDotNet/Templates/WasmCsProj.txt

@@ -13,7 +13,7 @@
     <OutputType>Exe</OutputType>
     <RuntimeConfig>Release</RuntimeConfig>
     <EnableDefaultCompileItems>false</EnableDefaultCompileItems>
-    <TargetFramework>$TFM$</TargetFramework>
+    <TargetFrameworks>$TFM$</TargetFrameworks>
     <AllowUnsafeBlocks>true</AllowUnsafeBlocks>
     <AppDir>$(PublishDir)</AppDir>
     <AssemblyName>$PROGRAMNAME$</AssemblyName>

src/BenchmarkDotNet/Toolchains/NativeAot/Generator.cs

@@ -129,7 +129,7 @@ private string GenerateProjectForNuGetBuild(string projectFilePath, BuildPartiti
     <ImportDirectoryBuildProps>false</ImportDirectoryBuildProps>
     <ImportDirectoryBuildTargets>false</ImportDirectoryBuildTargets>
     <OutputType>Exe</OutputType>
-    <TargetFramework>{TargetFrameworkMoniker}</TargetFramework>
+    <TargetFrameworks>{TargetFrameworkMoniker}</TargetFrameworks>
     <RuntimeIdentifier>{runtimeIdentifier}</RuntimeIdentifier>
     <RuntimeFrameworkVersion>{RuntimeFrameworkVersion}</RuntimeFrameworkVersion>
     <AssemblyName>{artifactsPaths.ProgramName}</AssemblyName>