Relaxation for 1.5

[hasufell]

• Relax upper bounds on filepath cabal#9523
• Relax filepath upper bound process#298
• Relax filepath upper bound composewell/streamly#2639
• Support filepath >= 1.5.0.0 and os-string, fixes #164 directory#165
• Support filepath >= 1.5.0.0 and os-string, fixes #222 win32#226

[mmhat]

@hasufell It appears all items in the list are done; Should this be closed then?