build.md: Use correct path for external_plugin_deps.bzl

Remove unnecessary duplication of cache-chroniclemap.

Change-Id: I028751c969a7e27995a8c657f79376c45d615644
diff --git a/src/main/resources/Documentation/build.md b/src/main/resources/Documentation/build.md
index 7e23698..652b328 100644
--- a/src/main/resources/Documentation/build.md
+++ b/src/main/resources/Documentation/build.md
@@ -14,8 +14,8 @@
 git clone https://gerrit.googlesource.com/gerrit
 git clone https://gerrit.googlesource.com/modules/cache-chroniclemap
 cd gerrit/plugins
-ln -s ../../cache-chroniclemap cache-chroniclemap
-ln -sf ../../external_plugin_deps.bzl .
+ln -s ../../cache-chroniclemap .
+ln -sf ../../cache-chroniclemap/external_plugin_deps.bzl .
 ```
 
 From the Gerrit source tree issue the command `bazelsk build plugins/cache-chroniclemap`.