Bump Npgsql from 6.0.2 to 8.0.3 in /Respawn.DatabaseTests

Bumps [Npgsql](https://github.com/npgsql/npgsql) from 6.0.2 to 8.0.3.
- [Release notes](https://github.com/npgsql/npgsql/releases)
- [Commits](npgsql/npgsql@v6.0.2...v8.0.3)

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

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

Respawn.DatabaseTests/Respawn.DatabaseTests.csproj

@@ -6,7 +6,7 @@
   <ItemGroup>
     <PackageReference Include="IBM.Data.DB2.Core" Version="3.1.0.500" />
     <PackageReference Include="MySql.Data" Version="8.0.27" />
-    <PackageReference Include="Npgsql" Version="6.0.2" />
+    <PackageReference Include="Npgsql" Version="8.0.3" />
     <PackageReference Include="NPoco.SqlServer" Version="5.3.2" />
     <PackageReference Include="Shouldly" Version="4.0.3" />
     <PackageReference Include="xunit" Version="2.4.1" />