add golang lint

Author: Cori1109

.github/workflows/test.yml

@@ -11,10 +11,10 @@ jobs:
     runs-on: ubuntu-latest
     steps:
 
-    - name: Set up Go 1.13
+    - name: Set up Go 1.16
       uses: actions/setup-go@v1
       with:
-        go-version: 1.13
+        go-version: 1.16
       id: go
 
     - name: Check out code into the Go module directory

.golangci.yml

@@ -0,0 +1,14 @@
+output:
+  format: colored-line-number
+  print-issued-lines: true
+  print-linter-name: true
+  uniq-by-line: true
+  path-prefix: ""
+  sort-results: false
+
+linters:
+  disable-all: true
+  fast: false
+  enable:
+    - unused
+    - typecheck