Add node 10, 12, 14, 16, and React 17 to Travis test matrix

This gives us better test coverage.

Author: lencioni

.travis.yml

@@ -1,5 +1,9 @@
 language: node_js
 node_js:
+  - "16"
+  - "14"
+  - "12"
+  - "10"
   - "8"
   - "6"
   - "4"
@@ -18,6 +22,7 @@ env:
     - REACT=15.4
     - REACT=15
     - REACT=16
+    - REACT=17
 sudo: false
 matrix:
   fast_finish: true