Try updating ubuntu

Required since support for 20.04 was dropped

Author: v0idpwn

.github/workflows/main.yml

@@ -10,7 +10,7 @@ jobs:
   test:
     name: Test (Elixir ${{ matrix.elixir }} | Erlang/OTP ${{ matrix.otp }})
     # We need Ubuntu 20.04 for now to test old OTP and Elixir versions.
-    runs-on: ubuntu-20.04
+    runs-on: ubuntu-22.04
     strategy:
       fail-fast: false
       matrix: