Update workflow Emacs version to 30.2

Author: jeffkreeftmeijer

.github/workflows/ert.yml

@@ -17,5 +17,5 @@ jobs:
       - uses: actions/checkout@v3
       - uses: purcell/setup-emacs@master
         with:
-          version: 28.2
+          version: 30.2
       - run: scripts/test

.github/workflows/markdown.yml

@@ -18,7 +18,7 @@ jobs:
           fetch-depth: 0
       - uses: purcell/setup-emacs@master
         with:
-          version: 28.2
+          version: 30.2
       - run: emacs --batch ox-html-markdown-style-footnotes.org --load scripts/readme.el/readme.el --eval "(readme/to-markdown \"README.md\")"
       - uses: stefanzweifel/git-auto-commit-action@v4
         with: