build(deps): bump Npgsql in /samples/dotnet/npgsql-sample (#1731)

Bumps [Npgsql](https://github.com/npgsql/npgsql) from 8.0.2 to 8.0.3.
- [Release notes](https://github.com/npgsql/npgsql/releases)
- [Commits](npgsql/npgsql@v8.0.2...v8.0.3)

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

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samples/dotnet/npgsql-sample/npgsql-sample.csproj

@@ -9,7 +9,7 @@
     </PropertyGroup>
 
     <ItemGroup>
-      <PackageReference Include="Npgsql" Version="8.0.2" />
+      <PackageReference Include="Npgsql" Version="8.0.3" />
       <PackageReference Include="Testcontainers" Version="3.8.0" />
     </ItemGroup>