ci: update Go versions in GitHub Actions workflow

- Update Go versions in the GitHub Actions workflow to include only `1.21`, `1.22`, and `1.23`

Signed-off-by: appleboy <[email protected]>

.github/workflows/go.yml

@@ -30,7 +30,7 @@ jobs:
     strategy:
       matrix:
         os: [ubuntu-latest, macos-latest]
-        go: [1.18, 1.19, "1.20", 1.21, 1.22]
+        go: [1.21, 1.22, 1.23]
         include:
           - os: ubuntu-latest
             go-build: ~/.cache/go-build