remove old golang versions in action script file, go1.21+ required for v1

Author: hedzr

.github/workflows/go.yml

@@ -32,7 +32,7 @@ jobs:
   test:
     strategy:
       matrix:
-        go-version: [ 1.18.x, 1.21.x ]   # 1.11.x, 1.12.x, 1.13.x,
+        go-version: [ 1.21.x ]   # 1.11.x, 1.12.x, 1.13.x,
         #os: [ubuntu-latest, macos-latest, windows-latest]
         os: [ ubuntu-latest ]
       fail-fast: false