actions: update to go 1.22/1.23

Also, bump actions/setup-go and actions/checkout to the latest
available.

.github/workflows/go.yml

@@ -8,17 +8,17 @@ jobs:
     strategy:
       matrix:
         os: [macOS-latest, ubuntu-latest]
-        goversion: [1.17, 1.18, 1.19]
+        goversion: ['1.22', '1.23']
     steps:
 
     - name: Set up Go ${{matrix.goversion}} on ${{matrix.os}}
-      uses: actions/setup-go@v3
+      uses: actions/setup-go@v5
       with:
         go-version: ${{matrix.goversion}}
       id: go
 
     - name: Check out code into the Go module directory
-      uses: actions/checkout@v1
+      uses: actions/checkout@v4
 
     - name: gofmt
       run: |