feat(mergeConfig): add defaultFinalizeContext

Makes it possible to modify the result based on the default function.

lib/merge-config.js

@@ -219,7 +219,7 @@ function mergeConfig(options, context, gitRawCommitsOpts, parserOpts, writerOpts
       }
 
       writerOpts = _.assign({
-          finalizeContext: function(context, writerOpts, filteredCommits, keyCommit, originalCommits) {
+          defaultFinalizeContext: function(context, writerOpts, filteredCommits, keyCommit, originalCommits) {
             var firstCommit = originalCommits[0];
             var lastCommit = originalCommits[originalCommits.length - 1];
             var firstCommitHash = firstCommit ? firstCommit.hash : null;
@@ -264,6 +264,9 @@ function mergeConfig(options, context, gitRawCommitsOpts, parserOpts, writerOpts
             }
 
             return context;
+          },
+          finalizeContext: function() {
+            return this.defaultFinalizeContext.apply(this, arguments);
           }
         },
         config.writerOpts, {

readme.md

@@ -188,7 +188,17 @@ See the [conventional-changelog-writer](https://github.com/conventional-changelo
 
 Finalize context is used for generating above context.
 
-**NOTE:** If you overwrite this value the above context defaults will be gone.
+**NOTE:** If you overwrite this value the above context defaults will be gone. If you want to modify the result based on the default function, you could do:
+
+```js
+finalizeContext: function() {
+  var newContext = this.defaultFinalizeContext.apply(this, arguments);
+
+  // Modify newContext
+
+  return newContext;
+}
+```
 
 ##### reverse