Upgrade JGit to 4.7.9.201904161809-r

This aligns with the version used in core Gerrit 2.14.20.

Change-Id: I541faea3113cfd841908dc1e72df33b4425dfc03
diff --git a/external_plugin_deps.bzl b/external_plugin_deps.bzl
index 49754b5..f4828c5 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:4.7.7.201812240805-r",
-        sha1 = "d2358e838084d2482d51b51b70fd34a356495925",
+            "org.eclipse.jgit:org.eclipse.jgit:4.7.9.201904161809-r",
+        sha1 = "14fb9628876e69d1921776c84c7343ddabe7db31",
     )
 
     maven_jar(