fix(ci): github runner deprecated ubuntu 20.04 (#560)

Author: canstand

.github/workflows/docs.yml

@@ -5,7 +5,7 @@ on:
 jobs:
   deploy:
     name: Deploy docs
-    runs-on: ubuntu-20.04
+    runs-on: ubuntu-latest
     steps:
     - uses: actions/checkout@v4
     - uses: ruby/setup-ruby@v1