Unable to install mapper-attachments plugin for Elastic Search 2.3.0

I am following the below link:

As per link when I am trying to install, I am getting the below error:
C:\Program Files\Elasticsearch>plugin install elasticsearch/elasticsearch-mapper
-attachments/elasticsearch repository
-> Installing elasticsearch/elasticsearch-mapper-attachments/elasticsearch...
Trying https://download.elastic.co/elasticsearch/elasticsearch-mapper-attachment
s/elasticsearch-mapper-attachments-elasticsearch.zip ...
Trying https://search.maven.org/remotecontent?filepath=elasticsearch/elasticsear
ch-mapper-attachments/elasticsearch/elasticsearch-mapper-attachments-elasticsear
ch.zip ...
Trying https://oss.sonatype.org/service/local/repositories/releases/content/elas
ticsearch/elasticsearch-mapper-attachments/elasticsearch/elasticsearch-mapper-at
tachments-elasticsearch.zip ...
Trying https://github.com/elasticsearch/elasticsearch-mapper-attachments/archive
/elasticsearch.zip ...
Trying https://github.com/elasticsearch/elasticsearch-mapper-attachments/archive
/master.zip ...
Downloading ....................................................................
................................................................................
................................................................................
................................................................................
................................................................................
................................................................................
................................................................................
................................................................................
................................................................................
................................................................................
................................................................................
................................................................................
................................................................................
................................................................................
................................................................................
................................................................................
................................................................................
................................................................................
................................................................................
................................................................................
................................................................................
................................................................................
................................................................................
................................................................................
.....................................DONE
Verifying https://github.com/elasticsearch/elasticsearch-mapper-attachments/arch
ive/master.zip checksums if available ...
NOTE: Unable to verify checksum for downloaded plugin (unable to find .sha1 or .
md5 file to verify)
ERROR: Could not find plugin descriptor 'plugin-descriptor.properties' in plugin
zip

Read the very first lines of the README:

IMPORTANT: this project now moved to elasticsearch repository (from elasticsearch 2.2.0):
mapper-attachments (documentation)