Update dependency org.junit:junit-bom to v5.13.0 (#767)

Co-authored-by: renovate[bot] <29139614+renovate[bot]@users.noreply.github.com>

Author: renovate[bot]

functions/pom.xml

@@ -20,7 +20,7 @@
     <spock.version.major>2.3</spock.version.major>
     <spock.version.groovyVariant>4.0</spock.version.groovyVariant>
     <spock.version>${spock.version.major}-groovy-${spock.version.groovyVariant}</spock.version>
-    <junit.version>5.12.2</junit.version>
+    <junit.version>5.13.0</junit.version>
     <functionTargetClass>gwc.GFunctionExecutor</functionTargetClass>
   </properties>