Use mattermost v5 module (#1192)

vendor/go.uber.org/zap/.travis.yml

@@ -1,21 +1,23 @@
 language: go
 sudo: false
-go:
-  - 1.11.x
-  - 1.12.x
+
 go_import_path: go.uber.org/zap
 env:
   global:
     - TEST_TIMEOUT_SCALE=10
-cache:
-  directories:
-    - vendor
-install:
-  - make dependencies
+    - GO111MODULE=on
+
+matrix:
+  include:
+  - go: 1.13.x
+  - go: 1.14.x
+    env: LINT=1
+
 script:
-  - make lint
+  - test -z "$LINT" || make lint
   - make test
   - make bench
+
 after_success:
   - make cover
   - bash <(curl -s https://codecov.io/bash)