[CI] Cancel previous runs that are not completed for a given workflow. (#666)

.github/workflows/build.yml

@@ -19,6 +19,10 @@ on:
       - 'examples/**'
       - '.dev_scripts/**'
 
+concurrency:
+  group: ${{ github.workflow }}-${{ github.ref }}
+  cancel-in-progress: true
+
 jobs:
   build_cpu:
     runs-on: ubuntu-18.04

.github/workflows/lint.yml

@@ -2,6 +2,10 @@ name: lint
 
 on: [push, pull_request]
 
+concurrency:
+  group: ${{ github.workflow }}-${{ github.ref }}
+  cancel-in-progress: true
+
 jobs:
   lint:
     runs-on: ubuntu-latest

.github/workflows/publish-to-pypi.yml

@@ -2,6 +2,10 @@ name: deploy
 
 on: push
 
+concurrency:
+  group: ${{ github.workflow }}-${{ github.ref }}
+  cancel-in-progress: true
+
 jobs:
   build-n-publish:
     runs-on: ubuntu-latest