Update minimum RAM for Flye

Hi!
To run, **Flye** needs to first get all the reads in the memory, therefore, the minimum RAM requirement equals the (uncompressed) reads file size. Would it be possible to modify the RAM to something like 1.2 times the reads file size?
Now it is:
```
toolshed.g2.bx.psu.edu/repos/bgruening/flye/flye/.*:
cores: 20
mem: 60
```
:)

Start by locating the Flye rule matching toolshed.g2.bx.psu.edu/repos/bgruening/flye/flye/.* and checking how its cores and mem values are defined. Determine whether the shared rules can derive memory from the uncompressed reads file size, then verify that the configured minimum is 1.2 times that size.

Written by the indexing model from the issue text.