ci: add golangci config

Author: ernado

.golangci.yml

@@ -0,0 +1,85 @@
+linters-settings:
+  govet:
+    check-shadowing: true
+  golint:
+    min-confidence: 0
+  gocyclo:
+    min-complexity: 10
+  maligned:
+    suggest-new: true
+  dupl:
+    threshold: 100
+  goconst:
+    min-len: 2
+    min-occurrences: 2
+  depguard:
+    list-type: blacklist
+    packages:
+      # logging is allowed only by logutils.Log, logrus
+      # is allowed to use only in logutils package
+      - github.com/sirupsen/logrus
+  misspell:
+    locale: US
+  lll:
+    line-length: 140
+  goimports:
+    local-prefixes: github.com/golangci/golangci-lint
+  gocritic:
+    enabled-tags:
+      - performance
+      - style
+      - experimental
+    disabled-checks:
+      - wrapperFunc
+      - commentFormatting # https://github.com/go-critic/go-critic/issues/755
+
+issues:
+  exclude-rules:
+    # Exclude some linters from running on tests files.
+    - path: _test\.go
+      linters:
+        - gocyclo
+        - errcheck
+        - dupl
+        - gosec
+
+    # Ease some gocritic warnings on test files.
+    - path: _test\.go
+      text: "(unnamedResult|exitAfterDefer)"
+      linters:
+        - gocritic
+
+    # Exclude known linters from partially hard-vendored code,
+    # which is impossible to exclude via "nolint" comments.
+    - path: internal/hmac/
+      text: "weak cryptographic primitive"
+      linters:
+        - gosec
+    - path: internal/hmac/
+      text: "Write\\` is not checked"
+      linters:
+        - errcheck
+
+    # Ease linting on benchmarking code.
+    - path: cmd/stun-bench/
+      linters:
+        - gosec
+        - errcheck
+  enable-all: true
+  disable:
+    - prealloc
+    - gochecknoglobals
+
+run:
+  skip-dirs:
+    - e2e
+    - fuzz
+    - testdata
+    - api
+
+# golangci.com configuration
+# https://github.com/golangci/golangci/wiki/Configuration
+service:
+  golangci-lint-version: 1.13.x # use fixed version to not introduce new linters unexpectedly
+  prepare:
+    - echo "here I can run custom commands, but no preparation needed"