Upgrade JGit to 4.11.9.201909030838-r

This aligns with the version used in latest core Gerrit 2.15.

Change-Id: I1ce1c83b5d415b403c1dc506679cd3ed309a802f
diff --git a/external_plugin_deps.bzl b/external_plugin_deps.bzl
index a2d5f0c..da241f8 100644
--- a/external_plugin_deps.bzl
+++ b/external_plugin_deps.bzl
@@ -125,8 +125,8 @@
     maven_jar(
         name = "jgit",
         artifact =
-            "org.eclipse.jgit:org.eclipse.jgit:4.9.8.201812241815-r",
-        sha1 = "dedb5d05a952551dc465611ebde3819d86bb22fc",
+            "org.eclipse.jgit:org.eclipse.jgit:4.11.9.201909030838-r",
+        sha1 = "3bc74ffed6186bf2fc37404216e5ef16f904d0b0",
     )
 
     maven_jar(