ci: update go testing versions (#124)

Author: black-06

.github/workflows/tests.yml

@@ -11,7 +11,7 @@ jobs:
   run-tests:
     strategy:
       matrix:
-        go: ['1.19', '1.18', '1.17']
+        go: ['1.21', '1.20', '1.19']
         platform: [ubuntu-latest]
     runs-on: ubuntu-latest
     services: