Update License to Elastic v2 (#944)

rules/linux/persistence_kernel_module_activity.toml

@@ -1,7 +1,7 @@
 [metadata]
 creation_date = "2020/02/18"
 maturity = "production"
-updated_date = "2021/02/16"
+updated_date = "2021/03/03"
 
 [rule]
 author = ["Elastic"]
@@ -15,7 +15,7 @@ false_positives = [
 from = "now-9m"
 index = ["auditbeat-*", "logs-endpoint.events.*"]
 language = "kuery"
-license = "Elastic License"
+license = "Elastic License v2"
 name = "Persistence via Kernel Module Modification"
 references = [
     "https://www.hackers-arise.com/single-post/2017/11/03/Linux-for-Hackers-Part-10-Loadable-Kernel-Modules-LKM",