chore: a pipeline to validate basic assumptions are stil fulfilled.

Running stress-test like baseline tests regularly should help us
assure that `crates-index-diff` operates as it should against a
real crates-index.

Author: Byron

.github/workflows/cron.yml

@@ -0,0 +1,15 @@
+name: cron
+
+on:
+  schedule: 
+    - cron: '0 13,1 * * *'
+  workflow_dispatch:
+
+jobs:
+  stress:
+    runs-on: ubuntu-latest
+    steps:
+    - uses: actions/checkout@v3
+    - uses: Swatinem/rust-cache@v2
+    - name: baseline
+      run: baseline-atomic