CI: Test only with recent stable erlang and elixir versions

.github/workflows/ci.yml

@@ -21,15 +21,8 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        otp: [23, 26, 27]
-        elixir: ['1.13', '1.17']
-        exclude:
-        - otp: '23.0'
-          elixir: '1.17'
-        - otp: '26'
-          elixir: '1.13'
-        - otp: '27'
-          elixir: '1.13'
+        otp: [25, 26, 27]
+        elixir: ['1.17']
     runs-on: ubuntu-20.04
 
     steps:
@@ -50,13 +43,6 @@ jobs:
       with:
         path: .ejabberd-modules/sources/ejabberd-contrib
 
-    - name: Get a compatible Rebar3
-      if: matrix.otp <= 23
-      run: |
-        rm rebar3
-        wget https://github.com/processone/ejabberd/raw/21.12/rebar3
-        chmod +x rebar3
-
     - name: Prepare libraries
       run: |
         sudo apt-get -qq update