deps: update npm to 6.13.0

6.13.0 (2019-11-05)

NEW FEATURES

• 4414b06d9 #273 add fund command (@ruyadorno)

DOCUMENTATION

• ae4c74d04 #274 migrate existing docs to gatsby (@claudiahdz)
• 4ff1bb180 #277 updated documentation copy (@oletizi)

BUG FIXES

• e4455409f #281 delete ps1 files on package removal (@NoDocCat)
• cd14d4701 #279 update supported node list to remove v6.0, v6.1, v9.0 - v9.2 (@ljharb)

DEPENDENCIES

• a37296b20 pacote@9.5.9
• d3cb3abe8 read-cmd-shim@1.0.5

TESTING

• 688cd97be #272 use github actions for CI (@JasonEtco)
• 9a2d8af84 #240 Clean up some flakiness and inconsistency (@isaacs)