Update CodSpeed workflow to v4 with OIDC authentication

.github/workflows/codspeed.yml

@@ -4,8 +4,14 @@ on:
   push:
     branches: [master, main]
   pull_request:
+  # `workflow_dispatch` allows CodSpeed to trigger backtest
+  # performance analysis in order to generate initial data.
   workflow_dispatch:
 
+permissions:
+  contents: read
+  id-token: write
+
 jobs:
   benchmarks:
     name: Run benchmarks
@@ -25,9 +31,9 @@ jobs:
       - run: pnpm install
 
       - name: Run benchmarks under CodSpeed
-        uses: CodSpeedHQ/action@v3
+        uses: CodSpeedHQ/action@v4
         with:
+          mode: simulation
           run: pnpm vitest bench --run --config vitest.bench.config.ts
-          token: ${{ secrets.CODSPEED_TOKEN }}
         env:
           NODE_ENV: production

README.md

@@ -1,5 +1,7 @@
 # intervaltree JS
 
+[![CodSpeed](https://img.shields.io/endpoint?url=https://codspeed.io/badge.json)](https://codspeed.io/hexsprite/intervaltree?utm_source=badge)
+
 A mutable, self-balancing interval tree for JavaScript/TypeScript.
 
 Written in TypeScript with no external dependencies. Uses an augmented AVL tree under the hood for O(log n) operations.