Fail to push Nuget package to the package registry in the air-gapped environment
Summary
When trying to push the Nuget package to the registry in the air-gapped environment, an error will occur.

Steps to reproduce
- Install GitLab without Internet connection.
- Add the Nuget source.
- Push the package.
wget -O microsoft.net.test.sdk.16.9.4.nupkg https://www.nuget.org/api/v2/package/Microsoft.NET.Test.Sdk/16.9.4
dotnet nuget add source -n gitlab-nuget "http://10.0.17.66/api/v4/projects/13/packages/nuget/index.json" -u dotnet-rw -p foo --store-password-in-clear-text
dotnet nuget push microsoft.net.test.sdk.16.9.4.nupkg -s "gitlab-nuget"
To trace this failure, we add the following codes to /lib/gitlab/url_blocker.rb:
Gitlab::AppLogger.warn("Address Info Url Is+ uri)
After adding the codes, we get the log:
URL is blocked: Host cannot be resolved or invalid
We find that when pushing the package to the registry, GitLab will cache and validate the icon url, license url and the project url where the package belong. Because there is no DNS records for these three urls in the air-gapped environment, the pushing keeps failing.
Edited by ZTZK
