remove go 1.20 unit test; it's no longer useful and lacks certain features

Author: brewmaster012

.github/workflows/ci.yml

@@ -11,7 +11,7 @@ jobs:
     runs-on: ubuntu-22.04
     strategy:
       matrix:
-        go-version: ["1.20", "1.22"]
+        go-version: ["1.22"]
     name: test go ${{ matrix.go-version}}
     steps:
       - uses: actions/checkout@v4