Bump log4jVersion from 2.19.0 to 2.20.0

Bumps `log4jVersion` from 2.19.0 to 2.20.0.

Updates `org.apache.logging.log4j:log4j-core` from 2.19.0 to 2.20.0
- [Release notes](https://github.com/apache/logging-log4j2/releases)
- [Changelog](https://github.com/apache/logging-log4j2/blob/2.x/CHANGELOG.adoc)
- [Commits](apache/logging-log4j2@rel/2.19.0...rel/2.20.0)

Updates `org.apache.logging.log4j:log4j-slf4j2-impl` from 2.19.0 to 2.20.0
- [Release notes](https://github.com/apache/logging-log4j2/releases)
- [Changelog](https://github.com/apache/logging-log4j2/blob/2.x/CHANGELOG.adoc)
- [Commits](apache/logging-log4j2@rel/2.19.0...rel/2.20.0)

---
updated-dependencies:
- dependency-name: org.apache.logging.log4j:log4j-core
  dependency-type: direct:production
  update-type: version-update:semver-minor
- dependency-name: org.apache.logging.log4j:log4j-slf4j2-impl
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>

build.gradle.kts

@@ -50,7 +50,7 @@ subprojects {
         set("creekVersion", "0.3.3-SNAPSHOT")
         set("spotBugsVersion", "4.6.0")         // https://mvnrepository.com/artifact/com.github.spotbugs/spotbugs-annotations
 
-        set("log4jVersion", "2.19.0")           // https://mvnrepository.com/artifact/org.apache.logging.log4j/log4j-core
+        set("log4jVersion", "2.20.0")           // https://mvnrepository.com/artifact/org.apache.logging.log4j/log4j-core
         set("guavaVersion", "31.1-jre")         // https://mvnrepository.com/artifact/com.google.guava/guava
         set("junitVersion", "5.9.2")            // https://mvnrepository.com/artifact/org.junit.jupiter/junit-jupiter-api
         set("junitPioneerVersion", "2.0.0")     // https://mvnrepository.com/artifact/org.junit-pioneer/junit-pioneer