update simulator to ubuntu 20.04 (#2463)

* fix sim build in 20.04

* run ci

* fix docker build

* restore ci cofnig

Co-authored-by: Willem Melching <willem.melching@gmail.com>
old-commit-hash: cc1bca542d8a12acc381fc3d284d37b57b12c6ee

.github/workflows/sim_tests.yaml

@@ -8,7 +8,7 @@ jobs:
     name: build container
     runs-on: ubuntu-20.04
     timeout-minutes: 50
-    if: github.event_name == 'schedule' && github.repository == 'commaai/openpilot'
+    if: github.repository == 'commaai/openpilot'
     steps:
     - uses: actions/checkout@v2
       with: