bump dependencies

package.json

@@ -47,7 +47,7 @@
   "dependencies": {
     "create-error-class": "^3.0.0",
     "duplexer3": "^0.1.4",
-    "get-stream": "^1.1.0",
+    "get-stream": "^2.3.0",
     "is-plain-obj": "^1.0.0",
     "is-redirect": "^1.0.0",
     "is-retry-allowed": "^1.0.0",
@@ -59,12 +59,12 @@
     "url-parse-lax": "^1.0.0"
   },
   "devDependencies": {
-    "ava": "^0.14.0",
+    "ava": "^0.16.0",
     "coveralls": "^2.11.4",
     "get-port": "^2.0.0",
-    "get-stream": "^1.1.0",
+    "get-stream": "^2.3.0",
     "into-stream": "^2.0.0",
-    "nyc": "^6.0.0",
+    "nyc": "^7.1.0",
     "pem": "^1.4.4",
     "pify": "^2.3.0",
     "tempfile": "^1.1.1",