Add linting configuration file and linting script

.golangci.yml

@@ -0,0 +1,67 @@
+linters-settings:
+  exhaustive:
+    default-signifies-exhaustive: true
+  errcheck:
+    check-type-assertions: true
+  goconst:
+    min-len: 2
+    min-occurrences: 3
+  gocritic:
+    enabled-tags:
+      - diagnostic
+      - experimental
+      - opinionated
+      - performance
+      - style
+  govet:
+    check-shadowing: true
+    enable:
+      - fieldalignment
+  nolintlint:
+    require-explanation: true
+    require-specific: true
+
+linters:
+  disable-all: true
+  enable:
+    - bodyclose
+    - dogsled
+    - dupl
+    - errcheck
+    - exportloopref
+    - exhaustive
+    - goconst
+    - gocritic
+    - gofmt
+    - goimports
+    - gomnd
+    - gocyclo
+    - gosec
+    - gosimple
+    - govet
+    - ineffassign
+    - misspell
+    - nolintlint
+    - nakedret
+    - prealloc
+    - predeclared
+    - revive
+    - staticcheck
+    - stylecheck
+    - thelper
+    - tparallel
+    - typecheck
+    - unconvert
+    - unparam
+    - unused
+    - whitespace
+    - wsl
+
+issues:
+  exclude-rules:
+    - path: _test\.go$
+      linters:
+        - goconst
+
+run:
+  issues-exit-code: 1

Makefile

@@ -31,3 +31,6 @@ coverage:
 	cat coverage.out | grep -v "/calls.go" | grep -v "custom_subscription_calls.go" | grep -v "subscription_calls.go" > coverage.final.out
 	go tool cover -func=coverage.final.out
 	rm coverage.out coverage.final.out
+
+lint:
+	golangci-lint run