Bump Npgsql from 6.0.5 to 6.0.6

Bumps [Npgsql](https://github.com/npgsql/npgsql) from 6.0.5 to 6.0.6.
- [Release notes](https://github.com/npgsql/npgsql/releases)
- [Commits](npgsql/npgsql@v6.0.5...v6.0.6)

---
updated-dependencies:
- dependency-name: Npgsql
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

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

src/HealthChecks.NpgSql/HealthChecks.NpgSql.csproj

@@ -8,7 +8,7 @@
   </PropertyGroup>
 
   <ItemGroup>
-    <PackageReference Include="Npgsql" Version="6.0.5" />
+    <PackageReference Include="Npgsql" Version="6.0.6" />
     <PackageReference Include="Microsoft.Extensions.Diagnostics.HealthChecks" Version="6.0.7" />
   </ItemGroup>