Bump NHibernate from 5.3.12 to 5.4.9 in /Tests.NHibernate.Spatial

Bumps NHibernate from 5.3.12 to 5.4.9.

---
updated-dependencies:
- dependency-name: NHibernate
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <support@github.com>

Author: dependabot[bot]

NHibernate.Spatial/NHibernate.Spatial.csproj

@@ -11,7 +11,7 @@
   <ItemGroup>
     <PackageReference Include="Microsoft.SourceLink.GitHub" Version="1.1.1" PrivateAssets="All" />
     <PackageReference Include="NetTopologySuite" Version="2.5.0" />
-    <PackageReference Include="NHibernate" Version="5.3.12" />
+    <PackageReference Include="NHibernate" Version="5.4.9" />
   </ItemGroup>
 
 </Project>