update travis

Author: IncSW

.travis.yml

@@ -1,18 +1,10 @@
 language: go
 sudo: false
 go:
-    - 1.11
-    - 1.12
-    - 1.13
-before_install:
-    - go get github.com/chihaya/chihaya/frontend/http/bencode
-    - go get github.com/jackpal/bencode-go
-    - go get github.com/marksamman/bencode
-    - go get github.com/zeebo/bencode
-    - go get github.com/nabilanam/bencode/decoder
-    - go get github.com/nabilanam/bencode/encoder
-    - go get github.com/mattn/goveralls
-    - go get github.com/stretchr/testify/assert
+    - 1.14
+    - 1.15
+env:
+  - GO111MODULE=on
 go_import_path: github.com/IncSW/go-bencode
 script:
     - make test