[#48058] GH Actions: Switched to using ubuntu-20.04

Signed-off-by: Grzegorz Latosinski <[email protected]>

.github/workflows/ci.yml

@@ -7,22 +7,25 @@ on:
         branches: [main]
 
 jobs:
-    readme-tests:
-        runs-on: ubuntu-latest
+    cancel-previous-job:
+        runs-on: ubuntu-20.04
         steps:
             - name: Cancel previous
               uses: styfle/[email protected]
               with:
                   access_token: ${{ github.token }}
+    readme-tests:
+        runs-on: ubuntu-20.04
+        steps:
             - name: Checkout sources
-              uses: actions/checkout@v3
+              uses: actions/checkout@v4
               with:
                   submodules: 'recursive'
                   lfs: true
             - name: Install tuttest dependencies
               run: |
                   sudo apt-get update -qqy
-                  sudo apt-get install -qqy --no-install-recommends python3 python3-pip git colorized-logs
+                  sudo apt-get install -qqy --no-install-recommends python3 python3-pip git-lfs colorized-logs
                   sudo pip3 install git+https://github.com/antmicro/tuttest.git
             - name: Run README.md snippets
               run: |