CI: use GitHub native concurrency to cancel workflows (#124)

Don't install/use custom
[styfle/cancel-workflow-action](https://github.com/styfle/cancel-workflow-action)
actions.

Instead, use the GitHub native
[concurrency](https://github.blog/changelog/2021-04-19-github-actions-limit-workflow-run-or-job-concurrency/)
property to cancel workflows.

- [x] Does not require a CHANGELOG entry

Signed-off-by: Adrian Catangiu <adrian@parity.io>
Co-authored-by: Bastian Köcher <git@kchr.de>

.github/workflows/changelog.yml

@@ -7,6 +7,7 @@ on:
   push:
     branches: ["main", "release-*"]
   pull_request:
+    types: [opened, reopened, synchronize, edited]
   workflow_dispatch:
 
 # cancel previous runs

.github/workflows/fmt.yml

@@ -6,6 +6,12 @@ on:
   pull_request:
   workflow_dispatch:
 
+# Cancel a currently running workflow from the same PR, branch or tag when a new workflow is
+# triggered (ref https://stackoverflow.com/a/72408109)
+concurrency:
+  group: ${{ github.workflow }}-${{ github.event.pull_request.number || github.ref }}
+  cancel-in-progress: true
+
 jobs:
   rustfmt:
     runs-on: ubuntu-22.04

.github/workflows/test.yml

@@ -51,11 +51,6 @@ jobs:
       matrix:
         runtime: ${{ fromJSON(needs.runtime-matrix.outputs.runtime) }}
     steps:
-      - name: Cancel previous runs
-        uses: styfle/cancel-workflow-action@b173b6ec0100793626c2d9e6b90435061f4fc3e5 # v0.11.0
-        with:
-          access_token: ${{ github.token }}
-
       - name: Install updates and protobuf-compiler
         run: sudo apt update && sudo apt install --assume-yes cmake protobuf-compiler