bump go versions

Author: Lightning

.github/workflows/ci.yml

@@ -9,15 +9,15 @@ jobs:
       - uses: actions/checkout@v3
       - uses: actions/setup-go@v3
         with:
-          go-version: "1.20"
+          go-version: "1.21"
       - name: Check diff between gofmt and code
         run: diff <(gofmt -d .) <(echo -n)
 
   test:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        go-version: ["1.18", "1.19", "1.20"]
+        go-version: ["1.20", "1.21"]
     steps:
       - uses: actions/checkout@v3
       - uses: actions/setup-go@v3
@@ -32,7 +32,7 @@ jobs:
       - uses: actions/checkout@v3
       - uses: actions/setup-go@v4
         with:
-          go-version: "1.20"
+          go-version: "1.21"
           cache: false
       - name: golangci-lint
         uses: golangci/golangci-lint-action@v3