I'm not sure why they recommend to put the credentials into a keystore.properties file and put that one into the project folder. I recommend to put the credentials into the ~/.gradle/gradle.properties file which is NOT part of the project and won't be committed to source control (don't mix up the project gradle.properies and the ~/.gradle/gradle.properties file, they are not the same).

The build pipeline provides the credentials but it won't build locally (debug build type) if you are not providing at least dummy values for the credentials.