CI: Include OTP28 in the erlang workflow version matrix

Author: the-mikedavis

.github/workflows/erlang.yml

@@ -1,16 +1,14 @@
 name: Test
 on:
   push:
-    branches:
-      - main
   pull_request:
 jobs:
   build:
     runs-on: ubuntu-latest
     strategy:
       fail-fast: false
       matrix:
-        otp_version: [26, 27]
+        otp_version: [26, 27, 28]
     steps:
     - name: CHECKOUT
       uses: actions/checkout@v2