CI: include go 1.20

Author: frankban

.github/workflows/ci.yaml

@@ -6,7 +6,7 @@ jobs:
     name: Build and Test
     strategy:
       matrix:
-        go: ['1.13', '1.14', '1.15', '1.16', '1.17', '1.18', '1.19']
+        go: ['1.13', '1.14', '1.15', '1.16', '1.17', '1.18', '1.19', '1.20']
     runs-on: ubuntu-latest
     steps:
     - uses: actions/checkout@v3