fix(package): update semver to version 7.1.2

Author: greenkeeper[bot]

package.json

@@ -28,7 +28,7 @@
     "rc": "^1.2.8",
     "read-pkg": "^5.0.0",
     "registry-auth-token": "^4.0.0",
-    "semver": "^6.3.0",
+    "semver": "^7.1.2",
     "tempy": "^0.3.0"
   },
   "devDependencies": {