Add files key to only publish required files

[timneutkens]

I noticed the tests etc being published to npm, this PR fixes that.

OLD

npm notice
npm notice 📦 [email protected]
npm notice === Tarball Contents ===
npm notice 925B package.json
npm notice 13B .eslintignore
npm notice 924B .eslintrc
npm notice 7.3kB .travis.yml
npm notice 1.2kB appveyor.yml
npm notice 222B index.js
npm notice 1.1kB LICENSE
npm notice 5.8kB readme.markdown
npm notice 155B example/async.js
npm notice 103B example/sync.js
npm notice 8.0kB lib/async.js
npm notice 354B lib/caller.js
npm notice 1.7kB lib/core.js
npm notice 2.1kB lib/core.json
npm notice 1.3kB lib/node-modules-paths.js
npm notice 348B lib/normalize-options.js
npm notice 4.5kB lib/sync.js
npm notice 86B test/.eslintrc
npm notice 2.7kB test/core.js
npm notice 799B test/dotdot.js
npm notice 39B test/dotdot/abc/index.js
npm notice 29B test/dotdot/index.js
npm notice 352B test/faulty_basedir.js
npm notice 975B test/filter_sync.js
npm notice 1.2kB test/filter.js
npm notice 2.0kB test/mock_sync.js
npm notice 5.2kB test/mock.js
npm notice 1.6kB test/module_dir.js
npm notice 51B test/module_dir/xmodules/aaa/index.js
npm notice 51B test/module_dir/ymodules/aaa/index.js
npm notice 51B test/module_dir/zmodules/bbb/main.js
npm notice 24B test/module_dir/zmodules/bbb/package.json
npm notice 2.0kB test/node_path.js
npm notice 22B test/node_path/x/aaa/index.js
npm notice 22B test/node_path/x/ccc/index.js
npm notice 22B test/node_path/y/bbb/index.js
npm notice 23B test/node_path/y/ccc/index.js
npm notice 3.2kB test/node-modules-paths.js
npm notice 182B test/nonstring.js
npm notice 909B test/pathfilter_sync.js
npm notice 2.2kB test/pathfilter.js
npm notice 0 test/pathfilter/deep_ref/main.js
npm notice 646B test/precedence.js
npm notice 24B test/precedence/aaa.js
npm notice 25B test/precedence/aaa/index.js
npm notice 28B test/precedence/aaa/main.js
npm notice 24B test/precedence/bbb.js
npm notice 44B test/precedence/bbb/main.js
npm notice 7.5kB test/resolver_sync.js
npm notice 13.0kB test/resolver.js
npm notice 0 test/resolver/baz/doom.js
npm notice 26B test/resolver/baz/package.json
npm notice 20B test/resolver/baz/quux.js
npm notice 0 test/resolver/browser_field/a.js
npm notice 0 test/resolver/browser_field/b.js
npm notice 63B test/resolver/browser_field/package.json
npm notice 1B test/resolver/cup.coffee
npm notice 20B test/resolver/dot_main/index.js
npm notice 20B test/resolver/dot_main/package.json
npm notice 20B test/resolver/dot_slash_main/index.js
npm notice 21B test/resolver/dot_slash_main/package.json
npm notice 20B test/resolver/foo.js
npm notice 116B test/resolver/incorrect_main/index.js
npm notice 27B test/resolver/incorrect_main/package.json
npm notice 0 test/resolver/mug.coffee
npm notice 0 test/resolver/mug.js
npm notice 0 test/resolver/other_path/lib/other-lib.js
npm notice 0 test/resolver/other_path/root.js
npm notice 20B test/resolver/quux/foo/index.js
npm notice 21B test/resolver/same_names/foo.js
npm notice 20B test/resolver/same_names/foo/index.js
npm notice 0 test/resolver/symlinked//node_modules/foo.js
npm notice 0 test/resolver/symlinked//symlink_target/.gitkeep
npm notice 111B test/resolver/without_basedir/main.js
npm notice 1.1kB test/shadowed_core.js
npm notice 0 test/shadowed_core/node_modules/util/index.js
npm notice 353B test/subdirs.js
npm notice 1.9kB test/symlinks.js
npm notice === Tarball Details ===
npm notice name: resolve
npm notice version: 1.8.1
npm notice filename: resolve-1.8.1.tgz
npm notice package size: 16.4 kB
npm notice unpacked size: 84.9 kB
npm notice shasum: 434ccd44bc1a5930131a74e9c939622bef0a8e2b
npm notice integrity: sha512-Hc7IJYsO2FJwB[...]YBr9c6DtXqdvA==
npm notice total files: 78
npm notice
resolve-1.8.1.tgz

NEW

npm notice
npm notice 📦 [email protected]
npm notice === Tarball Contents ===
npm notice 969B package.json
npm notice 222B index.js
npm notice 1.1kB LICENSE
npm notice 5.8kB readme.markdown
npm notice 8.0kB lib/async.js
npm notice 354B lib/caller.js
npm notice 1.7kB lib/core.js
npm notice 2.1kB lib/core.json
npm notice 1.3kB lib/node-modules-paths.js
npm notice 348B lib/normalize-options.js
npm notice 4.5kB lib/sync.js
npm notice === Tarball Details ===
npm notice name: resolve
npm notice version: 1.8.1
npm notice filename: resolve-1.8.1.tgz
npm notice package size: 6.9 kB
npm notice unpacked size: 26.3 kB
npm notice shasum: b157b77178e3bff873507f723af62ed00408c8f7
npm notice integrity: sha512-bkQoX8d2JaJqv[...]3Y4iBrsbbbDRw==
npm notice total files: 11
npm notice

[ljharb]

No. The files key is dangerous; if a new file is added to the package but omitted from this list, downstream consumers would break.

Separately, the tests are supposed to be published to npm. npm explore foo && npm install && npm test should always work.

[ljharb]

Duplicate of #176. Duplicate of #132. Duplicate of #128. Duplicate of #99. Duplicate of #59. Duplicate of #44.