Add plugin release semi-automatic script

Closes #13.

Author: dadoonet

README.md

@@ -5,14 +5,13 @@ The GCE Cloud plugin allows to use GCE API for the unicast discovery mechanism.
 
 In order to install the plugin, simply run: `bin/plugin -install elasticsearch/elasticsearch-cloud-gce/2.0.0.RC1`.
 
+* For 1.0.x elasticsearch versions, look at [master branch](https://github.com/elasticsearch/elasticsearch-cloud-gce/tree/master).
+* For 0.90.x elasticsearch versions, look at [1.x branch](https://github.com/elasticsearch/elasticsearch-cloud-gce/tree/1.x).
+
 |       GCE Cloud Plugin     |    elasticsearch    |   gce api    | Release date |
 |----------------------------|---------------------|--------------|:------------:|
-| 2.0.0-SNAPSHOT (master)    | 1.0.0.RC1 -> master |  1.17.0-rc   |              |
+| 2.0.0-SNAPSHOT             | 1.0.0.RC1 -> master |  1.17.0-rc   |  XXXX-XX-XX  |
 | 2.0.0.RC1                  | 1.0.0.RC1 -> master |  1.15.0-rc   |  2014-01-15  |
-| 1.3.0-SNAPSHOT (1.x)       | 0.90.3 -> 0.90      |  1.17.0-rc   |              |
-| 1.2.0                      | 0.90.3 -> 0.90      |  1.17.0-rc   |  2014-01-29  |
-| 1.1.0                      | 0.90.3 -> 0.90      |  1.15.0-rc   |  2013-08-09  |
-| 1.0.0                      | 0.90.0 -> 0.90.2    |  1.15.0-rc   |  2013-07-23  |
 
 
 Google Compute Engine Virtual Machine Discovery