Update CI files

Author: pulpbot

.github/template_gitref

@@ -1 +1 @@
-unknown
+2021.08.26-423-g87f69ce

.github/workflows/docs.yml

@@ -13,7 +13,7 @@ on:
 jobs:
   test:
     if: "endsWith(github.base_ref, 'main')"
-    runs-on: "ubuntu-20.04"
+    runs-on: "ubuntu-latest"
     defaults:
       run:
         working-directory: "pulp_python"
@@ -48,7 +48,7 @@ jobs:
 
   no-test:
     if: "!endsWith(github.base_ref, 'main')"
-    runs-on: "ubuntu-20.04"
+    runs-on: "ubuntu-latest"
     steps:
       - run: |
           echo "Skip docs testing on non-main branches."