RunsOn v3: switch disk=large → volume=80gb (#560)

Migrate the RunsOn self-hosted runner labels from the v2 `disk=large`
sizing to the v3 `volume=80gb` form across all three RunsOn workflows
(ci, cache, publish). `family=` and `image=` are unchanged.

Must merge together with this repo's move from the v2 to the v3 RunsOn
GitHub App: v2 does not understand `volume=`, and a v3 runner left on
`disk=large` boots the image default root volume.

Part of QuantEcon/lectures#5
See QuantEcon/meta#322

Co-authored-by: Claude Opus 4.8 <noreply@anthropic.com>

Author: mmcky

.github/workflows/cache.yml

@@ -6,7 +6,7 @@ on:
   workflow_dispatch:
 jobs:
   cache:
-    runs-on: "runs-on=${{ github.run_id }}/family=g4dn.2xlarge/image=quantecon_ubuntu2404/disk=large"
+    runs-on: "runs-on=${{ github.run_id }}/family=g4dn.2xlarge/image=quantecon_ubuntu2404/volume=80gb"
     steps:
       - uses: actions/checkout@v6
       - name: Setup Anaconda

.github/workflows/ci.yml

@@ -2,7 +2,7 @@ name: Build Project [using jupyter-book]
 on: [pull_request]
 jobs:
   preview:
-    runs-on: "runs-on=${{ github.run_id }}/family=g4dn.2xlarge/image=quantecon_ubuntu2404/disk=large"
+    runs-on: "runs-on=${{ github.run_id }}/family=g4dn.2xlarge/image=quantecon_ubuntu2404/volume=80gb"
     steps:
       - uses: actions/checkout@v6
         with:

.github/workflows/publish.yml

@@ -17,7 +17,7 @@ concurrency:
 jobs:
   publish:
     if: github.event_name == 'push' && startsWith(github.event.ref, 'refs/tags')
-    runs-on: "runs-on=${{ github.run_id }}/family=g4dn.2xlarge/image=quantecon_ubuntu2404/disk=large"
+    runs-on: "runs-on=${{ github.run_id }}/family=g4dn.2xlarge/image=quantecon_ubuntu2404/volume=80gb"
     environment:
       name: github-pages
       url: ${{ steps.deployment.outputs.page_url }}