Add linter

.github/workflows/lint.yml

@@ -0,0 +1,22 @@
+name: Lint
+# Lint runs golangci-lint over the entire cosmos-sdk repository
+# This workflow is run on every pull request and push to master
+# The `golangci` will pass without running if no *.{go, mod, sum} files have been changed.
+on:
+  pull_request:
+  push:
+    branches:
+      - develop
+jobs:
+  golangci:
+    name: golangci-lint
+    runs-on: ubuntu-latest
+    timeout-minutes: 6
+    steps:
+      - uses: actions/checkout@v2
+      - uses: golangci/golangci-lint-action@master
+        with:
+          # Required: the version of golangci-lint is required and must be specified without patch version: we always use the latest patch version.
+          version: v1.40
+          args: --timeout 10m
+          github-token: ${{ secrets.github_token }}

.golangci.yml

@@ -0,0 +1,78 @@
+run:
+  tests: false
+#   # timeout for analysis, e.g. 30s, 5m, default is 1m
+#   timeout: 5m
+
+linters:
+  disable-all: true
+  enable:
+    - bodyclose
+    - deadcode
+    - depguard
+    - dogsled
+    # - errcheck
+    - goconst
+    - gocritic
+    - gofmt
+    - goimports
+    - golint
+    - gosec
+    - gosimple
+    - govet
+    - ineffassign
+    - misspell
+    - nakedret
+    - prealloc
+    - exportloopref
+    - staticcheck
+    - structcheck
+    - stylecheck
+    - typecheck
+    - unconvert
+    - unused
+    - unparam
+    - misspell
+    # - wsl
+    - nolintlint
+
+issues:
+  exclude-rules:
+    - text: "Use of weak random number generator"
+      linters:
+        - gosec
+    - text: "comment on exported var"
+      linters:
+        - golint
+    - text: "don't use an underscore in package name"
+      linters:
+        - golint
+    - text: "ST1003:"
+      linters:
+        - stylecheck
+    # FIXME: Disabled until golangci-lint updates stylecheck with this fix:
+    # https://github.com/dominikh/go-tools/issues/389
+    - text: "ST1016:"
+      linters:
+        - stylecheck
+    - path: "legacy"
+      text: "SA1019:"
+      linters:
+        - staticcheck
+    - text: "ifElseChain:"
+      linters:
+        - gocritic
+
+  max-issues-per-linter: 10000
+  max-same-issues: 10000
+
+linters-settings:
+  dogsled:
+    max-blank-identifiers: 3
+  maligned:
+    # print struct with more effective memory layout or not, false by default
+    suggest-new: true
+  nolintlint:
+    allow-unused: false
+    allow-leading-space: true
+    require-explanation: false
+    require-specific: false