Add support for package-lock.json diffs posted to PRs

[davereid]

Much like the composer.lock diff tables that get posted to pull requests, could Drainpipe also provide the same when package-lock.json files are changed? Likely it should also use a sticky pull request comment like proposed in https://github.com/Lullabot/drainpipe/issues/332 and only if the package-lock.json file has been changed.

• [ ] Determine which NPM package to use to run the diff. https://www.npmjs.com/package/diff-lockfiles seems like a leading candidate.

[m4olivei]

https://www.npmjs.com/package/diff-lockfiles seems OK. A couple of things I noticed when I ran it:

• In my case, part of my work is updating node from v12 to the latest LTS (v20). That upgrade forces an update to package-lock.json to a new format, version 3. diff-lockfiles errored out on that difference. Not sure if that's b/c of different package-lock.jsonversion formats, or b/c it can't read olderpackage-lock.json` formats 🤷 .
• I also noticed that the output for new packages installed isn't great. Old version column reports null:

$ npm run diff-lockfiles

> ibm-cms-project@1.0.0 diff-lockfiles
> diff-lockfiles --color HEAD~1 HEAD

╔══════════════════════════════════════════════════════╤═════════════╤═════════════╗
║ ui.frontend.idl/package-lock.json                    │             │             ║
╟──────────────────────────────────────────────────────┼─────────────┼─────────────╢
║ package                                              │ old version │ new version ║
╟──────────────────────────────────────────────────────┼─────────────┼─────────────╢
║ node_modules/dns-packet/node_modules/ip              │ 1.1.8       │ 1.1.9       ║
╟──────────────────────────────────────────────────────┼─────────────┼─────────────╢
║ node_modules/follow-redirects                        │ 1.15.5      │ 1.15.6      ║
╟──────────────────────────────────────────────────────┼─────────────┼─────────────╢
║ node_modules/ip                                      │ 2.0.0       │ 2.0.1       ║
╟──────────────────────────────────────────────────────┼─────────────┼─────────────╢
║ node_modules/webpack-dev-server/node_modules/ip      │ 1.1.8       │ 1.1.9       ║
╟──────────────────────────────────────────────────────┼─────────────┼─────────────╢
║ node_modules/astral-regex                            │ null        │ 2.0.0       ║
╟──────────────────────────────────────────────────────┼─────────────┼─────────────╢
║ node_modules/diff-lockfiles                          │ null        │ 1.0.2       ║
╟──────────────────────────────────────────────────────┼─────────────┼─────────────╢
║ node_modules/diff-lockfiles/node_modules/chalk       │ null        │ 5.3.0       ║
╟──────────────────────────────────────────────────────┼─────────────┼─────────────╢
║ node_modules/diff-lockfiles/node_modules/commander   │ null        │ 11.1.0      ║
╟──────────────────────────────────────────────────────┼─────────────┼─────────────╢
║ node_modules/diff-lockfiles/node_modules/lru-cache   │ null        │ 6.0.0       ║
╟──────────────────────────────────────────────────────┼─────────────┼─────────────╢
║ node_modules/diff-lockfiles/node_modules/semver      │ null        │ 7.6.0       ║
╟──────────────────────────────────────────────────────┼─────────────┼─────────────╢
║ node_modules/lodash.truncate                         │ null        │ 4.4.2       ║
╟──────────────────────────────────────────────────────┼─────────────┼─────────────╢
║ node_modules/require-from-string                     │ null        │ 2.0.2       ║
╟──────────────────────────────────────────────────────┼─────────────┼─────────────╢
║ node_modules/slice-ansi                              │ null        │ 4.0.0       ║
╟──────────────────────────────────────────────────────┼─────────────┼─────────────╢
║ node_modules/table                                   │ null        │ 6.8.1       ║
╟──────────────────────────────────────────────────────┼─────────────┼─────────────╢
║ node_modules/table/node_modules/ajv                  │ null        │ 8.12.0      ║
╟──────────────────────────────────────────────────────┼─────────────┼─────────────╢
║ node_modules/table/node_modules/json-schema-traverse │ null        │ 1.0.0       ║
╚══════════════════════════════════════════════════════╧═════════════╧═════════════╝