chore: drop builds for ubuntu 20.04

Author: art049

.github/workflows/release.yml

@@ -10,10 +10,6 @@ jobs:
     strategy:
       matrix:
         runner:
-          - architecture: amd64
-            platform: ubuntu-20.04
-            ubuntu-version: 20.04
-            additional-deps: gcc-multilib libc6-dev-i386
           - architecture: amd64
             platform: ubuntu-22.04
             ubuntu-version: 22.04