Upgrade wiremock to 2.22.0

Change-Id: I7f40988a2e30033534bd36ac4ec9421908a77387
diff --git a/external_plugin_deps.bzl b/external_plugin_deps.bzl
index 3facffc..c5dc775 100644
--- a/external_plugin_deps.bzl
+++ b/external_plugin_deps.bzl
@@ -3,8 +3,8 @@
 def external_plugin_deps():
     maven_jar(
         name = "wiremock",
-        artifact = "com.github.tomakehurst:wiremock-standalone:2.21.0",
-        sha1 = "68807a39d80a19222316c57bf9a9d987ed26a0e3",
+        artifact = "com.github.tomakehurst:wiremock-standalone:2.22.0",
+        sha1 = "2f09e89af3ce7a68dcd4dbdc430e5a0fcf857a84",
     )
 
     maven_jar(