Update to Spring Security 5.8.0-RC1

Closes gh-949

gradle.properties

@@ -3,7 +3,7 @@ org.gradle.jvmargs=-Xmx3g -XX:+HeapDumpOnOutOfMemoryError
 org.gradle.parallel=true
 org.gradle.caching=true
 springFrameworkVersion=5.3.23
-springSecurityVersion=5.8.0-M3
+springSecurityVersion=5.8.0-RC1
 springJavaformatVersion=0.0.31
 springJavaformatExcludePackages=org/springframework/security/config org/springframework/security/oauth2
 checkstyleToolVersion=8.34