Add support to Ruby version 2.6

[mujz]

Issue #, if available: #214

Description of changes: Add support for Ruby 2.6 to the install script

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.

I already tested this and it seems to work just fine.

[coveralls]

Coverage remained the same at 91.679% when pulling daba769 on mujz:patch-1 into 7a58ba9 on aws:master.

[mujz]

Ping. Can an admin please look at this? It's very simple
@rohkat-aws @pmzara @annamataws

[inductor]

#196 This as well :(

[mujz]

Seems like nobody is maintaining this repo anymore :(

[rohkat-aws]

the ruby 2.6 will have to be tested internally before we release it as a supported ruby version @mujz

[mujz]

Great to hear from you @rohkat-aws. Thanks for your input!
That makes sense. Would you be able to provide any input on how long it might take for the internal testing? I understand that it's hard to give time estimates, so I won't hold you to it. Just knowing whether this is something that somebody is working on or not is all I'm looking to know here.

[mujz]

@rohkat-aws any update on this? Last I heard from you was about 2 months ago.