Update dependency NSubstitute to 5.3.0

Author: renovate[bot]

src/UnitTests/RxTelegram.Bot.UnitTests.csproj

@@ -9,7 +9,7 @@
     </PropertyGroup>
 
     <ItemGroup>
-        <PackageReference Include="NSubstitute" Version="5.1.0" />
+        <PackageReference Include="NSubstitute" Version="5.3.0" />
         <PackageReference Include="nunit" Version="4.2.2" />
         <PackageReference Include="NUnit3TestAdapter" Version="4.6.0" />
         <PackageReference Include="Microsoft.NET.Test.Sdk" Version="17.11.1" />