add linter & makefile, update go version=1.21

Author: dmitryburov

.github/workflows/tests.yml

@@ -23,5 +23,8 @@ jobs:
       - name: Install dependencies
         run: go mod download && go mod tidy
 
+      - name: Run lint
+        run: make lint
+
       - name: Run Tests
-        run: go test --short -v ./...
+        run: make test