Tweak a bit

Signed-off-by: Edward Z. Yang <[email protected]>

.github/workflows/CI.yml

@@ -6,24 +6,23 @@
 name: CI
 
 on:
+  pull_request:
   push:
     branches:
       - main
-      - master
     tags:
-      - '*'
-  pull_request:
-  workflow_dispatch:
+      - v*
+
+concurrency:
+  group: ${{ github.workflow }}-${{ github.event.pull_request.number || github.sha }}-${{ github.event_name == 'workflow_dispatch' }}
+  cancel-in-progress: true
 
 permissions:
   contents: read
 
 jobs:
   linux:
     runs-on: ubuntu-latest
-    strategy:
-      matrix:
-        target: [x86_64, x86, aarch64, armv7, s390x, ppc64le]
     steps:
       - uses: actions/checkout@v3
       - name: Build wheels
@@ -42,8 +41,6 @@ jobs:
   windows:
     runs-on: windows-latest
     strategy:
-      matrix:
-        target: [x64, x86]
     steps:
       - uses: actions/checkout@v3
       - name: Build wheels
@@ -60,9 +57,6 @@ jobs:
 
   macos:
     runs-on: macos-latest
-    strategy:
-      matrix:
-        target: [x86_64, aarch64]
     steps:
       - uses: actions/checkout@v3
       - name: Build wheels