update test workflow to go1.18

.github/workflows/test.yml

@@ -34,7 +34,7 @@ jobs:
       - name: Setup Go
         uses: actions/setup-go@v2
         with:
-          go-version: 1.17
+          go-version: 1.18
       - name: run tests
         run: |
             go test -p 1 ./... -v