Update dependency NSubstitute to 5.3.0 (#769)

Co-authored-by: renovate[bot] <29139614+renovate[bot]@users.noreply.github.com>

Author: renovate[bot]

src/Cake.Issues.PullRequests.AppVeyor.Tests/Cake.Issues.PullRequests.AppVeyor.Tests.csproj

@@ -4,7 +4,7 @@
   </PropertyGroup>
 
   <ItemGroup>
-    <PackageReference Include="NSubstitute" Version="5.1.0" />
+    <PackageReference Include="NSubstitute" Version="5.3.0" />
   </ItemGroup>
 
   <ItemGroup>

src/Cake.Issues.PullRequests.AzureDevOps.Tests/Cake.Issues.PullRequests.AzureDevOps.Tests.csproj

@@ -5,7 +5,7 @@
 
   <ItemGroup>
     <PackageReference Include="Cake.AzureDevOps" Version="4.0.0" />
-    <PackageReference Include="NSubstitute" Version="5.1.0" />
+    <PackageReference Include="NSubstitute" Version="5.3.0" />
   </ItemGroup>
 
   <ItemGroup>