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": {