Update the System.Net.Http integrations to support HttpRequestMessage.VersionPolicy

Directory.Build.targets

@@ -82,6 +82,7 @@
   <PropertyGroup
     Condition=" ('$(TargetFrameworkIdentifier)' == '.NETCoreApp' And $([MSBuild]::VersionGreaterThanOrEquals($(TargetFrameworkVersion), '5.0'))) ">
     <DefineConstants>$(DefineConstants);SUPPORTS_MULTIPLE_VALUES_IN_QUERYHELPERS</DefineConstants>
+    <DefineConstants>$(DefineConstants);SUPPORTS_HTTP_CLIENT_DEFAULT_REQUEST_VERSION_POLICY</DefineConstants>
   </PropertyGroup>
 
   <PropertyGroup

src/OpenIddict.Client.SystemNetHttp/OpenIddictClientSystemNetHttpHandlers.cs

@@ -257,6 +257,11 @@ public static partial class OpenIddictClientSystemNetHttpHandlers
             // If supported, import the HTTP version from the client instance.
             request.Version = client.DefaultRequestVersion;
 #endif
+
+#if SUPPORTS_HTTP_CLIENT_DEFAULT_REQUEST_VERSION_POLICY
+            // If supported, import the HTTP version policy from the client instance.
+            request.VersionPolicy = client.DefaultVersionPolicy;
+#endif
             HttpResponseMessage response;
 
             try

src/OpenIddict.Validation.SystemNetHttp/OpenIddictValidationSystemNetHttpHandlers.cs

@@ -256,6 +256,11 @@ public static partial class OpenIddictValidationSystemNetHttpHandlers
             // If supported, import the HTTP version from the client instance.
             request.Version = client.DefaultRequestVersion;
 #endif
+
+#if SUPPORTS_HTTP_CLIENT_DEFAULT_REQUEST_VERSION_POLICY
+            // If supported, import the HTTP version policy from the client instance.
+            request.VersionPolicy = client.DefaultVersionPolicy;
+#endif
             HttpResponseMessage response;
 
             try