bump github action go version to 1.21.4

.github/workflows/go.yml

@@ -5,15 +5,15 @@ env:
   # go needs absolute directories, using the $HOME variable doesn't work here.
   GOCACHE: /home/runner/work/go/pkg/build
   GOPATH: /home/runner/work/go
-  GO_VERSION: 1.17.5
+  GO_VERSION: 1.21.4
 
 jobs:
   build:
     name: Build
     runs-on: ubuntu-latest
     steps:
       - name: Set up Go
-        uses: actions/setup-go@v2
+        uses: actions/setup-go@v4
         with:
           go-version: ${{ env.GO_VERSION }}
 
@@ -29,7 +29,7 @@ jobs:
     if: false
     steps:
       - name: Set up Go
-        uses: actions/setup-go@v2
+        uses: actions/setup-go@v4
         with:
           go-version: ${{ env.GO_VERSION }}
 
@@ -77,7 +77,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - name: Set up Go
-        uses: actions/setup-go@v2
+        uses: actions/setup-go@v4
         with:
           go-version: ${{ env.GO_VERSION }}