Add Ruby version Check

[TApplencourt]

• 2.7.2 have be verified on Aurora (we should add test of ruby version on the CI -- either here or on the spack one)
• Removing Endless rand to avoid a syntax error when try to run iprof with ruby 2.5 (default on aurora -- reported by @sbekele81 )

    (0..).each do |i|
        ^
/home/sbekele/fabric_stat/bin/iprof:234: syntax error, unexpected keyword_end, expecting ')'
  end
  ^~~