Reuse dependencies from external_plugin_deps.bzl

This avoids having to edit both the WORKSPACE and the .bzl file
when updating dependencies, and removes the risk of forgetting to
update one of them.  Now only the external_plugin_deps.bzl file
needs to be updated.

Change-Id: Ic0ef2c9d7f99fb3b1e210c09e2f468c3ecdcd611
diff --git a/WORKSPACE b/WORKSPACE
index 3e7c59b..fc22763 100644
--- a/WORKSPACE
+++ b/WORKSPACE
@@ -23,22 +23,6 @@
 # Load release Plugin API
 gerrit_api()
 
-load("@com_googlesource_gerrit_bazlets//tools:maven_jar.bzl", "maven_jar")
+load("//:external_plugin_deps.bzl", "external_plugin_deps")
 
-maven_jar(
-    name = "mockito",
-    artifact = "org.mockito:mockito-core:2.7.21",
-    sha1 = "23e9f7bfb9717e849a05b84c29ee3ac723f1a653",
-)
-
-maven_jar(
-    name = "byte-buddy",
-    artifact = "net.bytebuddy:byte-buddy:1.6.11",
-    sha1 = "8a8f9409e27f1d62c909c7eef2aa7b3a580b4901",
-)
-
-maven_jar(
-    name = "objenesis",
-    artifact = "org.objenesis:objenesis:2.5",
-    sha1 = "612ecb799912ccf77cba9b3ed8c813da086076e9",
-)
+external_plugin_deps()
diff --git a/tools/bzl/maven_jar.bzl b/tools/bzl/maven_jar.bzl
new file mode 100644
index 0000000..2eabedb
--- /dev/null
+++ b/tools/bzl/maven_jar.bzl
@@ -0,0 +1 @@
+load("@com_googlesource_gerrit_bazlets//tools:maven_jar.bzl", "maven_jar")