Ignore eslint updates until supported by eslint-config-airbnb-base

Depends on airbnb/javascript#1834.

Signed-off-by: Kevin Locke <kevin@kevinlocke.name>

package.json

@@ -29,7 +29,7 @@
     "lint-js": "eslint . && echo ESLint passed.",
     "postpublish": "git -C doc push && git push --follow-tags origin master gh-pages && echo Remember to update GitHub Releases from CHANGELOG.md && echo until skywinder/github-changelog-generator#56 is fixed.",
     "postversion": "rimraf doc && git clone -b gh-pages -l -q . doc && npm run doc && git -C doc add . && git -C doc commit -n -m \"Docs for v$npm_package_version\"",
-    "preversion": "depcheck --ignores eslint-plugin-import,greenkeeper-lockfile --ignore-dirs doc && david && git-branch-is master && travis-status -b master -c -wx && appveyor-status -b master -c -w && istanbul check-coverage --statements 95 coverage/coverage.json",
+    "preversion": "depcheck --ignores eslint-plugin-import,greenkeeper-lockfile --ignore-dirs doc && david -i eslint && git-branch-is master && travis-status -b master -c -wx && appveyor-status -b master -c -w && istanbul check-coverage --statements 95 coverage/coverage.json",
     "start": "supervisor --quiet --no-restart-on exit --extensions js,json --ignore test --poll-interval 2000 server.js",
     "test": "npm run lint && npm run test-unit",
     "test-cov": "npm run lint && npm run test-unit-cov",
@@ -57,6 +57,11 @@
     "node": ">=6",
     "npm": ">=1.3.7"
   },
+  "greenkeeper": {
+    "ignore": [
+      "eslint"
+    ]
+  },
   "yargs": {
     "parse-numbers": false,
     "duplicate-arguments-array": false,