update changelog.txt

Author: hellertang

.changelog/1365.txt

@@ -1,8 +1,23 @@
 ```release-note:new-data-source
 	tencentcloud_dcdb_instances
+```
+
+```release-note:new-data-source
 	tencentcloud_dcdb_accounts
+```
+
+```release-note:new-data-source
 	tencentcloud_dcdb_databases
+```
+
+```release-note:new-data-source
 	tencentcloud_dcdb_parameters
+```
+
+```release-note:new-data-source
 	tencentcloud_dcdb_shards
+```
+
+```release-note:new-data-source
 	tencentcloud_dcdb_security_groups
 ```