[GHA] Get rid of Ubuntu 20 runners (#28938)

Support of Ubuntu 20.04 ends in April

Signed-off-by: Alina Kladieva <alina.kladieva@intel.com>

Author: akladiev

.github/workflows/build_doc.yml

@@ -11,7 +11,7 @@ concurrency:
 
 jobs:
   Build_Doc:
-    runs-on: ubuntu-20.04
+    runs-on: ubuntu-22.04
     steps:
       - name: Clone OpenVINO
         uses: actions/checkout@v4

.github/workflows/py_checks.yml

@@ -22,7 +22,7 @@ concurrency:
 
 jobs:
   linters:
-    runs-on: ubuntu-20.04
+    runs-on: ubuntu-22.04
     steps:
       - name: Clone OpenVINO
         uses: actions/checkout@v4