GHA CI: switch to Ubuntu latest stable version

.github/workflows/ci_ubuntu.yaml

@@ -9,7 +9,7 @@ concurrency:
 jobs:
   ci:
     name: Build
-    runs-on: ubuntu-20.04
+    runs-on: ubuntu-latest
 
     strategy:
       fail-fast: false
@@ -107,5 +107,5 @@ jobs:
       - name: Upload build artifacts
         uses: actions/upload-artifact@v3
         with:
-          name: build-info_ubuntu-20.04-x64_${{ matrix.qbt_gui }}_libtorrent-${{ matrix.libt_version }}_Qt-${{ matrix.qt_version }}
+          name: build-info_ubuntu-x64_${{ matrix.qbt_gui }}_libtorrent-${{ matrix.libt_version }}_Qt-${{ matrix.qt_version }}
           path: upload

.github/workflows/coverity-scan.yml

@@ -8,7 +8,8 @@ on:
 jobs:
   coverity_scan:
     name: Scan
-    runs-on: ubuntu-20.04
+    runs-on: ubuntu-latest
+
     steps:
       - name: Checkout repository
         uses: actions/checkout@v3