Update to Spring Security 6.1.8

Closes gh-1565

Author: jgrandja

gradle.properties

@@ -3,7 +3,7 @@ org.gradle.jvmargs=-Xmx3g -XX:+HeapDumpOnOutOfMemoryError
 org.gradle.parallel=true
 org.gradle.caching=true
 springFrameworkVersion=6.0.18
-springSecurityVersion=6.1.6
+springSecurityVersion=6.1.8
 springJavaformatVersion=0.0.38
 springJavaformatExcludePackages=org/springframework/security/config org/springframework/security/oauth2
 checkstyleToolVersion=8.34