Update MinVer to 3.1.0.

Author: bgrainger

src/Directory.Build.props

@@ -35,7 +35,7 @@
 
   <ItemGroup>
     <PackageReference Include="Microsoft.SourceLink.GitHub" Version="1.1.1" PrivateAssets="All"/>
-    <PackageReference Include="MinVer" Version="2.5.0">
+    <PackageReference Include="MinVer" Version="3.1.0">
       <IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>
       <PrivateAssets>all</PrivateAssets>
     </PackageReference>