DNF vs YUM, may want to add DNF to the package managers in this script, either/or with YUM

[SparkyzCodez]

I don't know if any RH based distros use DNF but do not have Yum installed. Currently, I do not know of any RH based distro that does not have YUM installed, but I just don't know for sure.

[rubo77]

If you think so, feel free to create a PR that adds it

[tuomaslaa]

If YUM is not installed, the script will give an unnecessary warning about a potential security threat.

[INFO] Looking for files containing log4j...
[WARNING] Maybe vulnerable, those files contain the name:
[INFO] using locate, which could be using outdated data. besure to have called updatedb recently

[rubo77]

@tuomaslaa this had nothing to do with yum installed. it is fixed since 958b83f