CHANGELOG: Fix typo “Breacking” (#333)

Author: alexislefebvre

CHANGELOG.md

@@ -5,7 +5,7 @@
 * Access to local part and domain part from EmailParser
 * Validations outside of the scope of the RFC will be considered "extra" validations, thus opening the door for adding new; will live in their own folder "extra" (as requested in #248, #195, #183). 
 
-## Breacking changes
+## Breaking changes
 
 * PHP version upgraded to match Symfony's (as of 12/2020).
 * DNSCheckValidation now fails for missing MX records. While the RFC argues that the existence of only A records to be valid, starting in v3 they will be considered invalid.