replace all oss.sonatype.org in code

[xsalefter]

Some test and code (like this one) use oss.sonatype.org to get artifact information.

While sonatype indeed successfully redirect requests targeted oss.sonatype.org to (likely) maven.org, there's time the redirection failed, give us either 504 error or something like this in various CIs.

Affected branches:

• maint-for-0-24-x
• master