increase default max files limit (#40)

<!-- This is an auto-generated comment: release notes by openai -->
### Summary by OpenAI

**Release Notes**

This pull request increases the default maximum number of files that can
be processed by the software from 40 to 80. This change was made in the
`src/options.ts` file.

- New Feature: Increased default max files limit from 40 to 80.
<!-- end of auto-generated comment: release notes by openai -->

action.yml

@@ -12,7 +12,7 @@ inputs:
   max_files:
     required: false
     description: 'Max files to review. Less than or equal to 0 means no limit.'
-    default: '40'
+    default: '80'
   temperature:
     required: false
     description: 'Temperature for GPT model'

src/options.ts

@@ -149,7 +149,7 @@ export class Options {
 
   constructor(
     debug: boolean,
-    max_files = '40',
+    max_files = '80',
     review_comment_lgtm = false,
     path_filters: string[] | null = null,
     system_message = '',