Fix Compile Error due to Nullability (#42825)

Current version yields this:
Nullability of type of parameter 'value' does not match overridden member.

Author: ardalis

samples/snippets/standard/data/sqlite/DapperSample/Program.cs

@@ -9,7 +9,7 @@ namespace DapperSample
     abstract class SqliteTypeHandler<T> : SqlMapper.TypeHandler<T>
     {
         // Parameters are converted by Microsoft.Data.Sqlite
-        public override void SetValue(IDbDataParameter parameter, T value)
+        public override void SetValue(IDbDataParameter parameter, T? value)
             => parameter.Value = value;
     }