Upgrade log4j to 2.15.0 - CVE-2021-44228

[rhowe]

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Not completely sure whether I got the dependency spec correct - ./gradlew dependencies didn't show log4j so I'm not really sure what's going on but hopefully this is a helpful nudge if nothing else.

[igr]

Yeah, it is not a dependency, but still OK :)

[rhowe]

Yeah, it is not a dependency, but still OK :)

Interesting - the Debian package of this library lists it as a dependency