Bump log4jVersion from 2.20.0 to 2.21.1 (#162)

Bumps `log4jVersion` from 2.20.0 to 2.21.1.

Updates `org.apache.logging.log4j:log4j-core` from 2.20.0 to 2.21.1

Updates `org.apache.logging.log4j:log4j-slf4j2-impl` from 2.20.0 to 2.21.1

---
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] <[email protected]>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

build.gradle.kts

@@ -35,7 +35,7 @@ allprojects {
 
 val creekVersion = "0.4.2-SNAPSHOT"
 val guavaVersion = "32.1.2-jre"         // https://mvnrepository.com/artifact/com.google.guava/guava
-val log4jVersion = "2.20.0"           // https://mvnrepository.com/artifact/org.apache.logging.log4j/log4j-core
+val log4jVersion = "2.21.1"           // https://mvnrepository.com/artifact/org.apache.logging.log4j/log4j-core
 val junitVersion = "5.10.0"            // https://mvnrepository.com/artifact/org.junit.jupiter/junit-jupiter-api
 val junitPioneerVersion = "2.1.0"     // https://mvnrepository.com/artifact/org.junit-pioneer/junit-pioneer
 val mockitoVersion = "5.5.0"          // https://mvnrepository.com/artifact/org.mockito/mockito-junit-jupiter