Fix and more cicd friendly

[Francois-Royer]

This pull request makes the following changes:

• fix unset/empty variables test
• fix wrong repo check
• add prefix NEXUS_ to credentials variables: when used on a CICD, it avoid collision with other credential
• increment version

[sonatypecla]

Thanks for the contribution! Before we can merge this, we need @Francois-Royer to sign the Sonatype Contributor License Agreement.

[DarthHater]

@dtshepherd wdyt?

[sonatypecla]

Thanks for the contribution! Before we can merge this, we need @maximestevenot to sign the Sonatype Contributor License Agreement.

[maximestevenot]

Hello I signed the document few months back. When do you plan to merge?