ensure that the auto-generated project alwas has target framework moniker in the output path, fixes #1562 (#1563)

Author: adamsitnik

src/BenchmarkDotNet/Templates/CsProj.txt

@@ -21,6 +21,7 @@
     $COPIEDSETTINGS$
     <!-- we set LangVersion after $COPIEDSETTINGS$ which might contain LangVersion copied from the benchmarks project -->
     <LangVersion Condition="'$(LangVersion)' == '' Or ($([System.Char]::IsDigit('$(LangVersion)', 0)) And '$(LangVersion)' &lt; '7.3')">latest</LangVersion>
+    <AppendTargetFrameworkToOutputPath>true</AppendTargetFrameworkToOutputPath>
   </PropertyGroup>
 
   <ItemGroup>