use the overload of String.Contains() which accepts StringComparison

Author: smdn

src/Directory.Build.props

@@ -19,7 +19,7 @@ SPDX-License-Identifier: MIT
   <ItemGroup>
     <PackageReference
       Include="Smdn.MSBuild.DefineConstants.NETSdkApi"
-      Version="[1.3.6]"
+      Version="[1.3.13]"
       PrivateAssets="all"
       IncludeAssets="build"
     />

src/Smdn.Reflection.ReverseGenerating.ListApi/Smdn.Reflection.ReverseGenerating.ListApi.Build/ProjectBuilder.cs

@@ -71,9 +71,14 @@ public static IEnumerable<FileInfo> Build(
     var proj = new Project(
       projectFile: projectFile.FullName,
       globalProperties: globalProps,
-      toolsVersion: RuntimeInformation.FrameworkDescription.Contains(".NET Framework")
-        ? "4.0"
-        : "Current"
+      toolsVersion:
+#if SYSTEM_STRING_CONTAINS_STRING_STRINGCOMPARISON
+        RuntimeInformation.FrameworkDescription.Contains(".NET Framework", StringComparison.OrdinalIgnoreCase)
+#else
+        RuntimeInformation.FrameworkDescription.Contains(".NET Framework")
+#endif
+          ? "4.0"
+          : "Current"
     );
 
     var buildRequest = new BuildRequestData(