Update release job to use ubuntu-latest

Update the release CI job to use ubuntu-latest instead of the now
unavailable ubuntu-20.04.

Normally we should update this via `dist generate`, but to keep changes
isolated we manually update just this field.

Author: wfchandler

.github/workflows/release.yml

@@ -50,7 +50,7 @@ on:
 jobs:
   # Run 'dist plan' (or host) to determine what tasks we need to do
   plan:
-    runs-on: "ubuntu-20.04"
+    runs-on: "ubuntu-latest"
     outputs:
       val: ${{ steps.plan.outputs.manifest }}
       tag: ${{ !github.event.pull_request && github.ref_name || '' }}
@@ -176,7 +176,7 @@ jobs:
     needs:
       - plan
       - build-local-artifacts
-    runs-on: "ubuntu-20.04"
+    runs-on: "ubuntu-latest"
     env:
       GH_TOKEN: ${{ secrets.GITHUB_TOKEN }}
       BUILD_MANIFEST_NAME: target/distrib/global-dist-manifest.json
@@ -236,7 +236,7 @@ jobs:
     env:
       GH_TOKEN: ${{ secrets.GITHUB_TOKEN }}
       AXO_RELEASES_TOKEN: ${{ secrets.AXO_RELEASES_TOKEN }}
-    runs-on: "ubuntu-20.04"
+    runs-on: "ubuntu-latest"
     outputs:
       val: ${{ steps.host.outputs.manifest }}
     steps:
@@ -276,7 +276,7 @@ jobs:
     needs:
       - plan
       - host
-    runs-on: "ubuntu-20.04"
+    runs-on: "ubuntu-latest"
     env:
       GH_TOKEN: ${{ secrets.GITHUB_TOKEN }}
       PLAN: ${{ needs.plan.outputs.val }}
@@ -321,7 +321,7 @@ jobs:
     needs:
       - plan
       - host
-    runs-on: "ubuntu-20.04"
+    runs-on: "ubuntu-latest"
     env:
       GH_TOKEN: ${{ secrets.GITHUB_TOKEN }}
       PLAN: ${{ needs.plan.outputs.val }}
@@ -372,7 +372,7 @@ jobs:
     # still allowing individual publish jobs to skip themselves (for prereleases).
     # "host" however must run to completion, no skipping allowed!
     if: ${{ always() && needs.host.result == 'success' && (needs.publish-homebrew-formula.result == 'skipped' || needs.publish-homebrew-formula.result == 'success') && (needs.publish-npm.result == 'skipped' || needs.publish-npm.result == 'success') && (needs.custom-publish-crates.result == 'skipped' || needs.custom-publish-crates.result == 'success') }}
-    runs-on: "ubuntu-20.04"
+    runs-on: "ubuntu-latest"
     env:
       GH_TOKEN: ${{ secrets.GITHUB_TOKEN }}
       AXO_RELEASES_TOKEN: ${{ secrets.AXO_RELEASES_TOKEN }}