add benchmarking in CI

Author: m-fila

.github/workflows/benchmark.yml

@@ -0,0 +1,36 @@
+name: Benchmark
+on:
+  pull_request:
+    branches:
+      - main
+permissions:
+  pull-requests: write    # action needs to post a comment
+
+jobs:
+  benchmark:
+    name: Julia ${{ matrix.version }} - ${{ matrix.platform.os }} - ${{ matrix.platform.arch }} - ${{ github.event_name }}
+    runs-on: ${{ matrix.platform.os }}
+    strategy:
+      matrix:
+        platform:
+          - os: ubuntu-latest
+            arch: x64
+          - os: ubuntu-24.04-arm
+            arch: aarch64
+        version:
+          - '1'
+          - 'lts'
+    steps:
+      - uses: actions/checkout@v4
+      - uses: julia-actions/setup-julia@v2
+        with:
+          version: ${{ matrix.version }}
+          arch: ${{ matrix.platform.arch }}
+      - name: Install dependencies
+        run: julia -e 'using Pkg; pkg"add PkgBenchmark [email protected]"'
+      - name: Run benchmarks
+        run: julia -e 'using BenchmarkCI; BenchmarkCI.judge(baseline = "origin/main")'
+      - name: Post results
+        run: julia -e 'using BenchmarkCI; BenchmarkCI.postjudge()'
+        env:
+          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}