actions: adopt Ubuntu 22.04, remove ESL repository

Signed-off-by: Matteo Cafasso <[email protected]>

.github/workflows/action.yml

@@ -2,23 +2,17 @@ name: build
 on: [push, pull_request]
 jobs:
   build:
-    runs-on: ubuntu-20.04
+    runs-on: ubuntu-22.04
     strategy:
       matrix:
-        erlang:
-          - 1:25.3-1
-        elixir:
-          - 1.13.4-1
         rmqref:
           - v3.12.x
     steps:
       - uses: actions/checkout@v2
       - name: Install Erlang and Elixir
         run: |
-          wget https://packages.erlang-solutions.com/erlang-solutions_2.0_all.deb
-          sudo dpkg -i erlang-solutions_2.0_all.deb
           sudo apt update
-          sudo apt install -y --allow-downgrades esl-erlang=${{ matrix.erlang }} elixir=${{ matrix.elixir }}
+          sudo apt install -y erlang elixir
       - name: Run tests
         run: |
           make current_rmq_ref=${{ matrix.rmqref }}