OpenSUSE Leap 15.2 is already available, and the upgrade process is simple.

– look into the upgrade release notes to make sure, you don’t run in any deprecations with your currently running software
– run a backup or a snapshot of the system, which will going to be upgraded.

After you read the release notes and run a backup, synchronize your system to the actual patch level:

zypper ref && zypper up 

Now you can safe update your repositories to 15.2 version:

sed -i 's/15.1/15.2/' /etc/zypp/repos.d/*
mv /etc/zypp/repos.d/openSUSE-15.1.0.repo /etc/zypp/repos.d/openSUSE-15.2.0.repo

If your repository file name is different from the default one, dont worry, this is not a problem at all. The refresh process merely replaces needed repos.

Now, you are ready to run the upgrade process:

zypper refresh && zypper dup

Your system will have to be restarted at once, for all the changes to take effect and, thus, run the new system.