meta: Remove codeowner protection from CHANGELOG.md (#3253)

As the changelog often needs to be updated with changes that have a
broader set of codeowners than the default `*`, we should exclude it
from codeowner protection to allow approvals by those codeowners, rather
than blocking PRs on the `*` rule only because of the changelog updates

Author: szokeasaurusrex

.github/CODEOWNERS

@@ -17,3 +17,6 @@
 /src/commands/build @getsentry/emerge-tools @getsentry/owners-sentry-cli
 /src/utils/build @getsentry/emerge-tools @getsentry/owners-sentry-cli
 /tests/integration/build @getsentry/emerge-tools @getsentry/owners-sentry-cli
+
+# Files without codeowner protection
+/CHANGELOG.md