Update ubuntu version in github actions

Author: MaximPlusov

.github/workflows/update-PDFA-profiles.yml

@@ -11,7 +11,7 @@ on:
 jobs:
   build:
     name: Checkout and Build
-    runs-on: ubuntu-20.04
+    runs-on: ubuntu-latest
 
     steps:
       - uses: actions/checkout@v2

.github/workflows/update-corpus-wiki.yml

@@ -8,7 +8,7 @@ on:
 jobs:
   build:
     name: Checkout and Build
-    runs-on: ubuntu-20.04
+    runs-on: ubuntu-latest
 
     steps:
       - uses: actions/checkout@v2