Add test to assert CHANGELOG format (#1582)

Author: jderusse

CHANGELOG.md

@@ -80,7 +80,7 @@
 
 ## 1.2.0
 
-### Deprecation
+### Deprecated
 
 - Protected methods `getServiceCode`, `getSignatureVersion` and `getSignatureScopeName` of `SqsClient` are deprecated and will be removed in 2.0
 
@@ -105,17 +105,17 @@
 
 ## 0.4.0
 
+### Removed
+
+- Dependency on `symfony/http-client-contracts`
+- All `validate()` methods on the inputs. They are merged with `request()`.
+
 ### Changed
 
 - Moved value objects to a dedicated namespace.
 - Results' `populateResult()` has only one argument. It takes a `AsyncAws\Core\Response`.
 - The `AsyncAws\Sqs\Enum\*`, `AsyncAws\Sqs\Input\*` and `AsyncAws\Sqs\ValueObject*` classes are marked final.
 
-### Removed
-
-- Dependency on `symfony/http-client-contracts`
-- All `validate()` methods on the inputs. They are merged with `request()`.
-
 ## 0.3.0
 
 ### Added