[BUG] When comparing with other branches, output file is blank

**Before we start...:**

- [x] I checked the documentation and found no answer
- [x] I checked to make sure that this issue has not already been filed
- [x] I'm reporting the issue to the correct repository (for multi-repository projects)

**Version, Branch, or Commit:**

`0.5.2`

**Expected behavior:**

Expected to compare skunk score between branches, and output the result to a desired file.

**Actual behavior:**

Skunk analysis runs well on shell with desired results, but the output file is blank.

**Steps to reproduce:**

From a feature branch:

```bash
skunk -b main -o skunk.txt
```

**Context and environment:**

- Operating System: Mac OS
- Operating System version: 12.2.1 (21D62)
- Ruby version: 2.7.3p183

**I will abide by the [code of conduct] (https://github.com/fastruby/skunk/blob/master/CODE_OF_CONDUCT.md)**