[#328] Bump Ubuntu runner for GitHub Actions.

Author: korydraughn

.github/workflows/build-docs.yml

@@ -2,7 +2,7 @@ name: build-docs
 on: [push, pull_request]
 jobs:
   build:
-    runs-on: ubuntu-20.04
+    runs-on: ubuntu-24.04
     steps:
       - uses: actions/checkout@v2
         with:

requirements.txt

@@ -10,7 +10,7 @@ mkdocs==1.2.4
 packaging==21.3
 pyparsing==3.0.7
 python-dateutil==2.8.2
-PyYAML==6.0
+PyYAML==6.0.2
 pyyaml-env-tag==0.1
 six==1.16.0
 typing-extensions==4.1.1