Update to slf4j-api 1.7.26

Fixes gh-6677

Author: jgrandja

gradle/dependency-management.gradle

@@ -192,7 +192,7 @@ dependencyManagement {
 		dependency 'org.slf4j:jcl-over-slf4j:1.7.26'
 		dependency 'org.slf4j:jul-to-slf4j:1.7.26'
 		dependency 'org.slf4j:log4j-over-slf4j:1.7.26'
-		dependency 'org.slf4j:slf4j-api:1.7.25'
+		dependency 'org.slf4j:slf4j-api:1.7.26'
 		dependency 'org.slf4j:slf4j-nop:1.7.25'
 		dependency 'org.sonatype.sisu.inject:cglib:2.2.1-v20090111'
 		dependency 'org.springframework.ldap:spring-ldap-core:2.3.2.RELEASE'