requirements: add matplotlib>=2.0 to the list of requirements
requirements: add matplotlib>=2.0 to the list of requirements

Former-commit-id: fdad535f378b3ca9a893ec0bcefeb847a1520563
Former-commit-id: 628fabe320804427a0eb299af56828019d0c7555 [formerly eb29ab33c0f05da975df8a571990feb78a1c857d] [formerly 67c56f6d106e5f3950f3aa9a765b57e91c876a8c [formerly 7fc1db73b5c8755c529ae7b466008660ae270aef]]
Former-commit-id: 2126ababd5765a3ab1be461bfc34474c92af879a [formerly 3985be32e62b585694e36556f79f4a8e16914117]
Former-commit-id: 1049809ea24593e9529b5688034c75d2ce471261
PolyJIT/benchbuild,PolyJIT/benchbuild,PolyJIT/benchbuild,PolyJIT/benchbuild