chore: test on beta in ci

Author: aminya

.github/workflows/CI.yml

@@ -15,7 +15,7 @@ jobs:
           - ubuntu-latest
           - macos-latest
           - windows-latest
-        atom_channel: [stable, nightly]
+        atom_channel: [stable, beta]
     steps:
       - uses: actions/checkout@v2
       - uses: UziTech/action-setup-atom@v1