Update github actions to test for later go versions

.github/workflows/ci.yml

@@ -6,13 +6,16 @@ on:
     branches: [ master ]
 jobs:
   ci:
+    strategy:
+      matrix:
+        go-version: [ '1.20', '1.21', '1.22', '1.23' ]
     runs-on: ubuntu-latest
     steps:
     - uses: actions/checkout@v4
     - name: Set up Go
       uses: actions/setup-go@v5
       with:
-        go-version-file: 'go.mod'
+        go-version: "${{ matrix.go }}"
     - name: Build
       run: |
         go mod tidy && git diff --exit-code