`Slurm.memory_from_tres` cannot handle decimal points

[Bubballoo3]

Describe the bug
The memory_from_tres method currently looks for \w+, which does not allow period characters. This is an issue because the values from slurm are not guaranteed to be integers. (See spec/fixtures/scripts/sacct.rb‎)

To Reproduce
Open a irb session with a job that has a non-integer memory value. The memory value returned is nil when it should not be.

irb(main):006> OodCore::Job::Adapters::Slurm.memory_from_tres('billing=1,cpu=1,mem=3.93G,node=1')
=> nil

Expected behavior
The regex should still match the floating point memory value and return the proper conversion to bytes