Make plugin version the same as Gerrit API version

Change-Id: I900b92bd3608f27adcad532e4fc9936df6fe7132
Signed-off-by: Edwin Kempin <edwin.kempin@sap.com>
diff --git a/VERSION b/VERSION
new file mode 100644
index 0000000..920fe49
--- /dev/null
+++ b/VERSION
@@ -0,0 +1,5 @@
+# Used by BUCK to include "Implementation-Version" in plugin Manifest.
+# If this file doesn't exist the output of 'git describe' is used
+# instead.
+PLUGIN_VERSION = '2.11'
+