Apply publish plugin to es-opensaml-security-api project (#104933)

Author: mark-vieira

x-pack/libs/es-opensaml-security-api/build.gradle

@@ -7,6 +7,7 @@
  */
 
 apply plugin: 'elasticsearch.build'
+apply plugin: 'elasticsearch.publish'
 apply plugin: 'com.github.johnrengelman.shadow'
 
 dependencies {