ci: bump linux to latest

Author: Borda

.github/dependabot.yml

@@ -15,5 +15,3 @@ updates:
       separator: "-"
     # Allow up to 5 open pull requests for GitHub Actions
     open-pull-requests-limit: 5
-    reviewers:
-      - "borda"

.github/workflows/ci_schema.yml

@@ -6,7 +6,7 @@ on:
 
 jobs:
   validate-schema:
-    runs-on: ubuntu-20.04
+    runs-on: ubuntu-latest
     timeout-minutes: 10
     steps:
       - name: Checkout

.github/workflows/docker-builds.yml

@@ -13,7 +13,7 @@ concurrency:
 
 jobs:
   build-push:
-    runs-on: ubuntu-20.04
+    runs-on: ubuntu-latest
     strategy:
       fail-fast: false
       matrix: