Set up workflow for golangci (#2020)

.github/workflows/linter.yml

@@ -0,0 +1,19 @@
+on: [push, pull_request]
+name: linter
+
+jobs:
+  lint:
+    strategy:
+      matrix:
+        go-version: [1.x]
+        platform: [ubuntu-latest]
+    runs-on: ${{ matrix.platform }}
+
+    steps:
+    - uses: actions/checkout@v2
+
+    - name: golangci-lint
+      uses: golangci/golangci-lint-action@5c56cd6c9dc07901af25baab6f2b0d9f3b7c3018 #v2.5.2
+      with:
+        version: v1.41
+        args: --verbose

.golangci.yml

@@ -0,0 +1,32 @@
+linters:
+  # TODO: fix errors so that all of the linters below pass.
+  # The linters that are commented out, as well as those explicitly disabled,
+  # are currently failing.  We should fix those failures or define exclusion
+  # rules, and then enable those linters.
+  enable:
+    - dogsled
+    - dupl
+    - gofmt
+    - goimports
+  # - gosec
+    - misspell
+    - nakedret
+  # - stylecheck
+  # - unconvert
+  # - unparam
+  # - whitespace
+  disable:
+    - errcheck
+    - gosimple
+    - staticcheck
+    - ineffassign
+    - unused
+issues: 
+  exclude-rules:
+  - linters:
+    - dogsled
+    text:  "declaration has 3 blank identifiers"
+    path: _test\.go
+  - linters:
+    - dupl
+    path: _test\.go

github/activity_notifications.go

@@ -51,7 +51,7 @@ type NotificationListOptions struct {
 //
 // GitHub API docs: https://docs.github.com/en/free-pro-team@latest/rest/reference/activity/#list-notifications-for-the-authenticated-user
 func (s *ActivityService) ListNotifications(ctx context.Context, opts *NotificationListOptions) ([]*Notification, *Response, error) {
-	u := fmt.Sprintf("notifications")
+	u := "notifications"
 	u, err := addOptions(u, opts)
 	if err != nil {
 		return nil, nil, err