chore: automatically cancel superseded Actions runs (#5)

Author: SimenB

.github/workflows/check.yml

@@ -4,6 +4,10 @@ on:
   push:
     branches: [main]
   pull_request:
+# Spend CI time only on latest ref: https://github.com/jonhoo/rust-ci-conf/pull/5
+concurrency:
+  group: ${{ github.workflow }}-${{ github.head_ref || github.run_id }}
+  cancel-in-progress: true
 name: check
 jobs:
   fmt:

.github/workflows/nostd.yml

@@ -4,6 +4,10 @@ on:
   push:
     branches: [main]
   pull_request:
+# Spend CI time only on latest ref: https://github.com/jonhoo/rust-ci-conf/pull/5
+concurrency:
+  group: ${{ github.workflow }}-${{ github.head_ref || github.run_id }}
+  cancel-in-progress: true
 name: no-std
 jobs:
   nostd:

.github/workflows/safety.yml

@@ -4,6 +4,10 @@ on:
   push:
     branches: [main]
   pull_request:
+# Spend CI time only on latest ref: https://github.com/jonhoo/rust-ci-conf/pull/5
+concurrency:
+  group: ${{ github.workflow }}-${{ github.head_ref || github.run_id }}
+  cancel-in-progress: true
 name: safety
 jobs:
   sanitizers:

.github/workflows/scheduled.yml

@@ -6,6 +6,10 @@ on:
   pull_request:
   schedule:
     - cron:  '7 7 * * *'
+# Spend CI time only on latest ref: https://github.com/jonhoo/rust-ci-conf/pull/5
+concurrency:
+  group: ${{ github.workflow }}-${{ github.head_ref || github.run_id }}
+  cancel-in-progress: true
 name: rolling
 jobs:
   # https://twitter.com/mycoliza/status/1571295690063753218

.github/workflows/test.yml

@@ -4,6 +4,10 @@ on:
   push:
     branches: [main]
   pull_request:
+# Spend CI time only on latest ref: https://github.com/jonhoo/rust-ci-conf/pull/5
+concurrency:
+  group: ${{ github.workflow }}-${{ github.head_ref || github.run_id }}
+  cancel-in-progress: true
 name: test
 jobs:
   required: