upgrade linter and cleanup makefile (#126)

.github/workflows/go.yml

@@ -18,21 +18,19 @@ jobs:
         os: [ubuntu-latest]
     steps:
       - name: Set up Go ${{ matrix.go-version }} on ${{ matrix.os }}
-        uses: actions/setup-go@v1
+        uses: actions/setup-go@v2
         with:
           go-version: ${{ matrix.go-version }}
         id: go
 
       - name: Check out code into the Go module directory
-        uses: actions/checkout@v1
+        uses: actions/checkout@v2
 
       - name: Build on ${{ matrix.os }}
         env:
           GO111MODULE: on
           GOOS: linux
         run: |
-          curl -sSfL https://raw.githubusercontent.com/golangci/golangci-lint/master/install.sh | sh -s -- -b $(go env GOPATH)/bin v1.24.0
-          $(go env GOPATH)/bin/golangci-lint run --timeout=5m --config ./.golangci.yml
-          go mod vendor
-          go test -v -race ./...
+          make verifiers
+          make test
           make mcs