offliner tool needs to download artifacts from http://repo.spring.io/plugins-release but is not Authorized

The offliner tool for 7.3.1 is configured to also download artifacts from Maven repository http://repo.spring.io/plugins-release.
It seems some artifacts like

com/github/ipfs/java-ipfs-api/v1.2.2/

may only be available from this Maven repository.
While these artifacts seem to be available on this Maven repository
http://repo.spring.io/plugins-release/com/github/ipfs/java-ipfs-api/v1.2.2/

... the download fails as authentication is required for downloading.

We need to enhance the offliner tool to allow for such authentication or fetch them from a different repository that does not require authentication.