Update :servlet:spring-boot:java:saml2:identity-provider to 7

servlet/spring-boot/java/saml2/identity-provider/gradle.properties

@@ -1,4 +1,4 @@
 version=6.1.1
-spring-security.version=6.5.0-SNAPSHOT
+spring-security.version=7.0.0-SNAPSHOT
 org.gradle.jvmargs=-Xmx6g -XX:+HeapDumpOnOutOfMemoryError
 org.gradle.caching=true