Don't recurse into submodules on `recursive: true`

[LandonTClipp]

Description

This PR changes mockery to not recurse into paths that contain a go.mod submodule. This is to help support monorepos that contain many modules. In this case, mockery should not be recursing into these because it causes issues, like in issue #706.

• Fixes #706.

Type of change

• [x] Bug fix (non-breaking change which fixes an issue)
• [ ] New feature (non-breaking change which adds functionality)
• [ ] Breaking change (fix or feature that would cause existing functionality to not work as expected)
• [ ] This change requires a documentation update

Version of Golang used when building/testing:

• [ ] 1.11
• [ ] 1.12
• [ ] 1.13
• [ ] 1.14
• [ ] 1.15
• [ ] 1.16
• [ ] 1.17
• [ ] 1.18
• [ ] 1.19
• [x] 1.20

[codecov[bot]]

Codecov Report

Attention: 5 lines in your changes are missing coverage. Please review.

Comparison is base (446e0bf) 75.16639% compared to head (b248492) 75.17584%.

Files	Patch %	Lines
pkg/config/config.go	73.68421%	4 Missing and 1 partial :warning:

Additional details and impacted files

```diff @@ Coverage Diff @@ ## master #740 +/- ## =================================================== + Coverage 75.16639% 75.17584% +0.00944% =================================================== Files 10 10 Lines 2404 2417 +13 =================================================== + Hits 1807 1817 +10 - Misses 459 461 +2 - Partials 138 139 +1 ```

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