feat(travis-ci): use golangci-lint

deprecate go 1.10.x and 1.11.x

.golangci.yml

@@ -0,0 +1,25 @@
+run:
+  deadline: 5m
+
+linters:
+  enable:
+    - deadcode
+    - errcheck
+    - gas
+    - goconst
+    - goimports
+    - golint
+    - govet
+    - ineffassign
+    - interfacer
+    - maligned
+    - megacheck
+    - structcheck
+    - unconvert
+    - varcheck
+  enable-all: false
+  disable-all: true
+#  presets:
+#    - bugs
+#    - unused
+  fast: false

.travis.yml

@@ -1,28 +1,24 @@
 language: go
 
 stages:
-  - diff
+  - lint
   - test
 
 go:
-  - 1.10.x
-  - 1.11.x
   - 1.12.x
   - tip
 
+env: GO111MODULE=on
+before_install: go get -u github.com/kyoh86/richgo
+script:
+  - richgo test -v ./...
+  - go build
+
 matrix:
   allow_failures:
     - go: tip
   include:
-    - stage: diff
+    - stage: lint
       go: 1.12.x
-      script: diff -u <(echo -n) <(gofmt -d -s .)
-
-before_install: go get -u github.com/kyoh86/richgo
-
-script:
-  - richgo test -v ./...
-  - go build
-  - if [ -z $NOVET ]; then
-      diff -u <(echo -n) <(go vet . 2>&1 | grep -vE 'ExampleCommand|bash_completions.*Fprint');
-    fi
+      before_install: curl -sfL https://install.goreleaser.com/github.com/golangci/golangci-lint.sh | sh -s -- -b $(go env GOPATH)/bin latest
+      script: golangci-lint run -v