ci: test cancelling stale actions (#851)

Use Github Action's concurrency settings to cancel old actions in favour of newer ones.

.github/workflows/ci.yml

@@ -1,11 +1,11 @@
-# Main CI pipeline to validate PRs.
+# Main CI workflow to validate PRs.
 #
-# CI pipeline based on:
+# CI workflow based on:
 # - https://github.com/heim-rs/heim/blob/master/.github/workflows/ci.yml
 # - https://github.com/BurntSushi/ripgrep/blob/master/.github/workflows/ci.yml
 # - https://www.reillywood.com/blog/rust-faster-ci/
 #
-# CI pipeline should do:
+# It should do the following:
 # - cargo fmt on supported platforms
 # - cargo test on supported platforms, cargo check on unsupported
 # - cargo clippy after (apparently faster) on supported platforms
@@ -24,6 +24,10 @@ env:
   CARGO_PROFILE_DEV_DEBUG: 0
   CARGO_HUSKY_DONT_INSTALL_HOOKS: true
 
+concurrency:
+  group: ${{ github.workflow }}-${{ github.ref }}
+  cancel-in-progress: true
+
 jobs:
   # Runs rustfmt + tests + clippy on the main supported platforms.
   supported:
@@ -54,7 +58,6 @@ jobs:
         id: skip_check
         uses: fkirc/skip-duplicate-actions@f11521568414503656a5af807dc3018c012552c4 # v5.2.0
         with:
-          concurrent_skipping: "same_content_newer"
           skip_after_successful_duplicate: "true"
           paths: '[".cargo/**", ".github/workflows/ci.yml", "sample_configs/**", "src/**", "tests/**", "build.rs", "Cargo.lock", "Cargo.toml", "clippy.toml", "rustfmt.toml"]'
           do_not_skip: '["workflow_dispatch", "push"]'
@@ -209,7 +212,6 @@ jobs:
         id: skip_check
         uses: fkirc/skip-duplicate-actions@f11521568414503656a5af807dc3018c012552c4 # v5.2.0
         with:
-          concurrent_skipping: "same_content_newer"
           skip_after_successful_duplicate: "true"
           paths: '[".cargo/**", ".github/workflows/ci.yml", "sample_configs/**", "src/**", "tests/**", "build.rs", "Cargo.lock", "Cargo.toml", "clippy.toml", "rustfmt.toml"]'
           do_not_skip: '["workflow_dispatch", "push"]'

.github/workflows/coverage.yml

@@ -12,6 +12,10 @@ on:
 env:
   CARGO_INCREMENTAL: 0
 
+concurrency:
+  group: ${{ github.workflow }}-${{ github.ref }}
+  cancel-in-progress: true
+
 jobs:
   pre_job:
     runs-on: ubuntu-latest
@@ -21,7 +25,6 @@ jobs:
       - id: skip_check
         uses: fkirc/skip-duplicate-actions@f11521568414503656a5af807dc3018c012552c4 # v5.2.0
         with:
-          concurrent_skipping: "same_content_newer"
           skip_after_successful_duplicate: "false"
           paths: '["tests/**", "src/**", ".github/workflows/coverage.yml", ".cargo/**", "Cargo.toml", "Cargo.lock", "build.rs"]'
           do_not_skip: '["workflow_dispatch", "push"]'

.github/workflows/docs.yml

@@ -1,3 +1,5 @@
+# Workflow to deploy mkdocs documentation.
+
 name: docs
 on:
   workflow_dispatch:

.github/workflows/post-release.yml

@@ -1,4 +1,5 @@
 # Actions to run after releasing a version, like generating documentation via mkdocs or notifying packaging repos.
+
 name: post-release
 
 on:

.github/workflows/test-docs.yml

@@ -1,8 +1,14 @@
+# Small CI workflow to test if mkdocs documentation can be successfully built.
+
 name: test-docs
 on:
   workflow_dispatch:
   pull_request:
 
+concurrency:
+  group: ${{ github.workflow }}-${{ github.ref }}
+  cancel-in-progress: true
+
 jobs:
   pre_job:
     runs-on: ubuntu-latest