FIx typo.

CONTRIBUTING.md

@@ -66,7 +66,7 @@
       * `detect-secrets scan --update .secrets.baseline` to update the secret baseline, then
       * `detect-secrets audit .secrets.baseline` to tag it as a false positive if relevant.
 
-## Testing recommandations
+## Testing recommendations
 
 Behaviour driven development (upon [TDD](https://dannorth.net/2012/05/31/bdd-is-like-tdd-if/)) is recommanded for all new developments.