chore(package): update semver to version 7.1.0 (#198)

Author: greenkeeper[bot]

package.json

@@ -39,7 +39,7 @@
     "long": "^4.0.0",
     "pre-commit": "^1.2.2",
     "proxyquire": "^2.1.3",
-    "semver": "^6.3.0",
+    "semver": "^7.1.0",
     "standard": "^14.0.0",
     "tap": "^12.6.5",
     "tap-mocha-reporter": "^3.0.9",