Run tests on Ubuntu and cancel earlier PR runs

.github/workflows/draft-pdf.yml

@@ -10,6 +10,10 @@ on:
       - paper.bib
       - architecture.png
 
+concurrency:
+  group: ${{ github.workflow }}-${{ github.event.pull_request.number || github.run_id }}
+  cancel-in-progress: ${{ github.event_name == 'pull_request' }}
+
 jobs:
   paper:
     runs-on: ubuntu-latest

.github/workflows/pr_code_changes.yaml

@@ -14,6 +14,10 @@ on:
       - src/policyengine/data/bundle/manifest.json
   workflow_dispatch:
 
+concurrency:
+  group: ${{ github.workflow }}-${{ github.event.pull_request.number || github.run_id }}
+  cancel-in-progress: ${{ github.event_name == 'pull_request' }}
+
 jobs:
   check-changelog:
     name: Check changelog fragment
@@ -127,7 +131,7 @@ jobs:
       - name: Verify bundle packages
         run: policyengine bundle verify --country us --country uk --packages-only --json
   Test:
-    runs-on: macos-latest
+    runs-on: ubuntu-latest
     strategy:
       fail-fast: false
       matrix:

.github/workflows/pr_docs_changes.yaml

@@ -11,6 +11,10 @@ on:
       - .github/**
   workflow_dispatch:
 
+concurrency:
+  group: ${{ github.workflow }}-${{ github.event.pull_request.number || github.run_id }}
+  cancel-in-progress: ${{ github.event_name == 'pull_request' }}
+
 jobs:
   Test:
     runs-on: ubuntu-latest

.github/workflows/push.yaml

@@ -39,7 +39,7 @@ jobs:
 
   Test:
     if: github.event.head_commit.message != 'Update package version'
-    runs-on: macos-latest
+    runs-on: ubuntu-latest
     strategy:
       fail-fast: false
       matrix:

changelog.d/545.changed.md

@@ -0,0 +1 @@
+Run the full Python test matrices on GitHub-hosted Ubuntu machines and cancel earlier workflow runs when a pull request receives a new commit.