+ gem update --system ERROR: Error installing rubygems-update:

[maanisim]

Issue on Ruby-EC2Instance-appmesh-workshop instances:

Successfully installed bundler-1.17.3
Parsing documentation for bundler-1.17.3
Done installing documentation for bundler after 3 seconds
38 gems installed
+ gem update --system
ERROR:  Error installing rubygems-update:
        There are no versions of rubygems-update (= 3.4.21) compatible with your Ruby & RubyGems
        rubygems-update requires Ruby version >= 2.6.0. The current ruby version is 2.5.0.
ERROR:  While executing gem ... (NoMethodError)
    undefined method `version' for nil:NilClass
Updating rubygems-update

Workaround:
Commenting out the gem update --system as it causes bootstrap failure