deps: bump npm-package-arg to v7

BREAKING CHANGE: this drops support for ancient node versions. See npm/hosted-git-info#38 (comment)

Author: isaacs

package-lock.json

@@ -29,7 +29,7 @@
  "license": "ISC",
  "dependencies": {
  "figgy-pudding": "^3.5.1",
- "npm-package-arg": "^6.0.0",
+ "npm-package-arg": "^7.0.0",
  "semver": "^5.4.1"
  },
  "devDependencies": {