chore: fix codecov and bump deps

.babelrc

@@ -5,5 +5,6 @@
         "node": "6.4.0"
       }
     }]
-  ]
+  ],
+  "sourceMaps": "both"
 }

README.md

@@ -126,7 +126,7 @@ app.listen();
 [MIT](LICENSE) © [Nick Baugh](http://niftylettuce.com/)
 
 
-##
+## 
 
 [npm]: https://www.npmjs.com/
 

package.json

@@ -21,26 +21,26 @@
   ],
   "dependencies": {},
   "devDependencies": {
-    "@babel/cli": "^7.4.4",
-    "@babel/core": "^7.4.5",
-    "@babel/preset-env": "^7.4.5",
-    "@commitlint/cli": "^8.0.0",
-    "@commitlint/config-conventional": "^8.0.0",
-    "ava": "^2.1.0",
+    "@babel/cli": "^7.6.0",
+    "@babel/core": "^7.6.0",
+    "@babel/preset-env": "^7.6.0",
+    "@commitlint/cli": "^8.2.0",
+    "@commitlint/config-conventional": "^8.2.0",
+    "ava": "^2.4.0",
     "codecov": "^3.5.0",
-    "cross-env": "^5.2.0",
-    "eslint": "^5.16.0",
+    "cross-env": "^6.0.0",
+    "eslint": "^6.4.0",
     "eslint-config-xo-lass": "^1.0.3",
-    "eslint-plugin-node": "^9.1.0",
+    "eslint-plugin-node": "^10.0.0",
     "express": "^4.17.1",
     "fixpack": "^2.3.1",
-    "husky": "^2.4.1",
-    "koa": "^2.7.0",
-    "lint-staged": "^8.2.1",
+    "husky": "^3.0.5",
+    "koa": "^2.8.1",
+    "lint-staged": "^9.2.5",
     "nyc": "^14.1.1",
-    "remark-cli": "^6.0.1",
-    "remark-preset-github": "^0.0.13",
-    "rimraf": "^2.6.3",
+    "remark-cli": "^7.0.0",
+    "remark-preset-github": "^0.0.16",
+    "rimraf": "^3.0.0",
     "supertest": "^4.0.2",
     "xo": "^0.24.0"
   },
@@ -102,20 +102,18 @@
   ],
   "license": "MIT",
   "lint-staged": {
-    "linters": {
-      "*.js": [
-        "xo --fix",
-        "git add"
-      ],
-      "*.md": [
-        "remark . -qfo",
-        "git add"
-      ],
-      "package.json": [
-        "fixpack",
-        "git add"
-      ]
-    }
+    "*.js": [
+      "xo --fix",
+      "git add"
+    ],
+    "*.md": [
+      "remark . -qfo",
+      "git add"
+    ],
+    "package.json": [
+      "fixpack",
+      "git add"
+    ]
   },
   "main": "lib/index.js",
   "prettier": {