API not detected

[svaningelgem]

Describe the bug
What I added (as written in the README file near the bottom):

    implementation 'com.github.imDMK.DoubleJump:doublejump-api:2.1.5'

How do you trigger it?
gradle build

Additional context
Output from the console:

   > Could not find com.github.imDMK.DoubleJump:doublejump-api:2.1.5.
     Searched in the following locations:
       - https://repo.maven.apache.org/maven2/com/github/imDMK/DoubleJump/doublejump-api/2.1.5/doublejump-api-2.1.5.pom
       - https://hub.spigotmc.org/nexus/content/repositories/snapshots/com/github/imDMK/DoubleJump/doublejump-api/2.1.5/doublejump-api-2.1.5.pom
       - https://jitpack.io/com/github/imDMK/DoubleJump/doublejump-api/2.1.5/doublejump-api-2.1.5.pom

When going to (part of) that last URL, I'm getting:

https://jitpack.io/com/github/imDMK/DoubleJump/doublejump-api/2.1.5/
==> File not found. Build Error

All versions from the 2.1.* branch have issues. First available version seems to be 2.07 (not 2.0.7).

Is it possible to fix the builds?

Thanks