build(deps): bump Npgsql in /samples/cloud-run/dotnet

Bumps [Npgsql](https://github.com/npgsql/npgsql) from 7.0.6 to 8.0.3.
- [Release notes](https://github.com/npgsql/npgsql/releases)
- [Commits](npgsql/npgsql@v7.0.6...v8.0.3)

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

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

samples/cloud-run/dotnet/dotnet.csproj

@@ -7,7 +7,7 @@
   </PropertyGroup>
 
   <ItemGroup>
-    <PackageReference Include="Npgsql" Version="7.0.6" />
+    <PackageReference Include="Npgsql" Version="8.0.3" />
   </ItemGroup>
 
 </Project>