remove coveralls and set 100% coverage threshold

package.json

@@ -8,7 +8,7 @@
     "lib"
   ],
   "scripts": {
-    "test": "npm run lint && NODE_ENV=test nyc ava",
+    "test": "npm run lint && NODE_ENV=test nyc --check-coverage --lines 100 ava",
     "lint": "zeit-eslint --ext .jsx,.js .",
     "lint-staged": "git diff --diff-filter=ACMRT --cached --name-only '*.js' '*.jsx' | xargs zeit-eslint"
   },
@@ -28,7 +28,6 @@
     "@zeit/eslint-config-node": "0.2.13",
     "@zeit/git-hooks": "0.1.4",
     "ava": "0.23.0",
-    "coveralls": "3.0.0",
     "eslint": "4.19.1",
     "husky": "0.14.3",
     "nyc": "11.3.0",
@@ -54,4 +53,4 @@
   "git": {
     "pre-commit": "lint-staged"
   }
-}
+}

yarn.lock

@@ -1132,16 +1132,6 @@ core-util-is@1.0.2, core-util-is@~1.0.0:
   version "1.0.2"
   resolved "https://registry.yarnpkg.com/core-util-is/-/core-util-is-1.0.2.tgz#b5fd54220aa2bc5ab57aab7140c940754503c1a7"
 
-coveralls@3.0.0:
-  version "3.0.0"
-  resolved "https://registry.yarnpkg.com/coveralls/-/coveralls-3.0.0.tgz#22ef730330538080d29b8c151dc9146afde88a99"
-  dependencies:
-    js-yaml "^3.6.1"
-    lcov-parse "^0.0.10"
-    log-driver "^1.2.5"
-    minimist "^1.2.0"
-    request "^2.79.0"
-
 create-error-class@^3.0.0:
   version "3.0.2"
   resolved "https://registry.yarnpkg.com/create-error-class/-/create-error-class-3.0.2.tgz#06be7abef947a3f14a30fd610671d401bca8b7b6"
@@ -2417,7 +2407,7 @@ js-tokens@^3.0.0, js-tokens@^3.0.2:
   version "3.0.2"
   resolved "https://registry.yarnpkg.com/js-tokens/-/js-tokens-3.0.2.tgz#9866df395102130e38f7f996bceb65443209c25b"
 
-js-yaml@^3.6.1, js-yaml@^3.8.2, js-yaml@^3.9.1:
+js-yaml@^3.8.2, js-yaml@^3.9.1:
   version "3.11.0"
   resolved "https://registry.yarnpkg.com/js-yaml/-/js-yaml-3.11.0.tgz#597c1a8bd57152f26d622ce4117851a51f5ebaef"
   dependencies:
@@ -2531,10 +2521,6 @@ lcid@^1.0.0:
   dependencies:
     invert-kv "^1.0.0"
 
-lcov-parse@^0.0.10:
-  version "0.0.10"
-  resolved "https://registry.yarnpkg.com/lcov-parse/-/lcov-parse-0.0.10.tgz#1b0b8ff9ac9c7889250582b70b71315d9da6d9a3"
-
 levn@^0.3.0, levn@~0.3.0:
   version "0.3.0"
   resolved "https://registry.yarnpkg.com/levn/-/levn-0.3.0.tgz#3b09924edf9f083c0490fdd4c0bc4421e04764ee"
@@ -2617,10 +2603,6 @@ lodash@^4.13.1, lodash@^4.17.4, lodash@^4.3.0:
   version "4.17.5"
   resolved "https://registry.yarnpkg.com/lodash/-/lodash-4.17.5.tgz#99a92d65c0272debe8c96b6057bc8fbfa3bed511"
 
-log-driver@^1.2.5:
-  version "1.2.7"
-  resolved "https://registry.yarnpkg.com/log-driver/-/log-driver-1.2.7.tgz#63b95021f0702fedfa2c9bb0a24e7797d71871d8"
-
 lolex@^2.2.0, lolex@^2.3.2:
   version "2.3.2"
   resolved "https://registry.yarnpkg.com/lolex/-/lolex-2.3.2.tgz#85f9450425103bf9e7a60668ea25dc43274ca807"
@@ -3510,7 +3492,7 @@ request@2.81.0:
     tunnel-agent "^0.6.0"
     uuid "^3.0.0"
 
-request@2.83.0, request@^2.79.0:
+request@2.83.0:
   version "2.83.0"
   resolved "https://registry.yarnpkg.com/request/-/request-2.83.0.tgz#ca0b65da02ed62935887808e6f510381034e3356"
   dependencies: