ci: add multi-version Go testing and optimize coverage upload

Author: yarlson

.github/workflows/test.yml

@@ -9,18 +9,22 @@ on:
 jobs:
   test:
     runs-on: ubuntu-latest
+    strategy:
+      matrix:
+        goVersion: [ "1.11", "1.21", "1.23" ]
     steps:
       - uses: actions/checkout@v4
 
       - name: Set up Go
         uses: actions/setup-go@v4
         with:
-          go-version: '1.21'
+          go-version: ${{ matrix.goVersion }}
 
       - name: Run tests with coverage
         run: go test -race -coverprofile=coverage.txt -covermode=atomic ./...
 
       - name: Upload coverage reports to Codecov
+        if: ${{ matrix.goVersion == '1.23' }}
         uses: codecov/codecov-action@v5
         with:
           token: ${{ secrets.CODECOV_TOKEN }}

go.mod

@@ -1,3 +1,3 @@
 module github.com/yarlson/pin
 
-go 1.21
+go 1.11