fix(ci): only test on go1.16

.github/workflows/go.yml

@@ -7,16 +7,12 @@ on:
   pull_request:
 jobs:
   test:
-    strategy:
-      matrix:
-        go-version: [1.13.x, 1.14.x, 1.15.x]
-        platform: [ubuntu-latest]
-    runs-on: ${{ matrix.platform }}
+    runs-on: ubuntu-latest
     steps:
-      - name: Setup Go ${{ matrix.go-version }}
+      - name: Setup Go
         uses: actions/setup-go@v1
         with:
-          go-version: ${{ matrix.go-version }}
+          go-version: 1.16.x
       - name: Checkout code into the Go module directory
         uses: actions/checkout@v1
       - name: Install dependencies