update yum dependency to version 3

# Please enter the commit message for your changes. Lines starting
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# Author:    Bradley Smith <brad.smith@sendgrid.com>
#
# On branch master
# Changes to be committed:
#   (use "git reset HEAD^1 <file>..." to unstage)
#
#	modified:   CHANGELOG.md
#	modified:   README.md
#	modified:   metadata.rb
#
