Adds a benchmark workflow (#40)

* Adds a benchmark workflow

* Disables non-criterion benchmarks

* fmt

Author: arcanis

.github/workflows/bench.yml

@@ -0,0 +1,14 @@
+name: Benchmark
+
+on:
+  pull_request:
+
+jobs:
+  bench:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: taiki-e/checkout-action@v1
+
+      - uses: boa-dev/criterion-compare-action@v3
+        with:
+          branchName: ${{github.base_ref}}