update GitHub workflows

Author: mattn

.github/workflows/go.yaml

@@ -14,7 +14,7 @@ jobs:
     strategy:
       matrix:
         os: [ubuntu-latest, macos-latest]
-        go: ['1.19', '1.20', '1.21']
+        go: ['1.20', '1.23', '1.24']
       fail-fast: false
     env:
       OS: ${{ matrix.os }}