Add golangci-lint configuration

Author: Chris Gilmer

.golangci.yml

@@ -0,0 +1,35 @@
+linters-settings:
+  govet:
+    check-shadowing: true
+  goimports:
+    # put imports beginning with prefix after 3rd-party packages;
+    # it's a comma-separated list of prefixes
+    local-prefixes: github.com/trussworks/find-guardduty-user
+
+linters:
+  enable:
+    - deadcode
+    - errcheck
+    - gofmt
+    - goimports
+    - golint
+    - gosec
+    - govet
+    - ineffassign
+    - staticcheck
+    - structcheck
+    - typecheck
+    - varcheck
+  disable:
+    - gosimple #deprecated https://github.com/golangci/golangci-lint/issues/357
+    - unused #deprecated https://github.com/dominikh/go-tools/tree/master/cmd/unused
+  fast: false
+
+issues:
+  # golangci-lint excludes by default some checks they consider "annoying"
+  # A better practice is for each repo to choose which ones to disable
+  exclude-use-default: false
+  fix: true
+
+run:
+  modules-download-mode: readonly