improve linting

.golangci.yml

@@ -0,0 +1,22 @@
+linters-settings:
+  gocyclo:
+    # minimal code complexity to report, 30 by default (but we recommend 10-20)
+    min-complexity: 10
+  gocritic:
+     disabled-checks:
+      - ifElseChain
+
+linters:
+  enable:
+  - megacheck
+  - govet
+  - golint
+  - gocyclo
+  - gosec
+  - unconvert
+  - dupl
+  - maligned
+  - nakedret
+  - prealloc
+  - scopelint
+  - gocritic