Upgraded psutil (#8217)
Upgraded psutil (#8217)

### Problem

`psutil==5.4.8` causes issues when setting up Pants. Refer to #8189.

### Solution

Upgraded `psutil==5.6.3` seems to have resolved the issue.

### Result

Pants can now initialize when using Python 3.7. Fixes #8189.
tdyas/pants,pantsbuild/pants,tdyas/pants,wisechengyi/pants,benjyw/pants,pantsbuild/pants,tdyas/pants,tdyas/pants,tdyas/pants,jsirois/pants,jsirois/pants,tdyas/pants,benjyw/pants,pantsbuild/pants,jsirois/pants,tdyas/pants,benjyw/pants,wisechengyi/pants,pantsbuild/pants,tdyas/pants,benjyw/pants,pantsbuild/pants,pantsbuild/pants,wisechengyi/pants,wisechengyi/pants,wisechengyi/pants,wisechengyi/pants,benjyw/pants,wisechengyi/pants,tdyas/pants,benjyw/pants,pantsbuild/pants,benjyw/pants,wisechengyi/pants,wisechengyi/pants