Fix tests: remove deprecated environments & old form-data

Author: ThisIsMissEm

.travis.yml

@@ -1,11 +1,9 @@
 language: node_js
 node_js:
-  - "4"
-  - "6"
   - "8"
-  - "node"
+  - "10"
 env:
-  - FORMDATA_VERSION=1.0.0
+  # - FORMDATA_VERSION=1.0.0
   - FORMDATA_VERSION=2.1.0
 before_script:
   - 'if [ "$FORMDATA_VERSION" ]; then npm install form-data@^$FORMDATA_VERSION; fi'

package.json

@@ -60,5 +60,8 @@
   },
   "dependencies": {
     "web-streams-polyfill": "^1.3.2"
+  },
+  "peerDependencies": {
+    "form-data": ">= 2.1.0"
   }
 }