Clone recursively for docker build workflow

[clenk]

Description

The GitHub workflow for building docker images errored out because the plugin submodules weren't being cloned properly. This should fix it.

Type of change

• Bug fix (non-breaking change which fixes an issue)

How Has This Been Tested?

Checklist:

• My code follows the style guidelines of this project
• I have performed a self-review of my own code
• I have made corresponding changes to the documentation
• I have added tests that prove my fix is effective or that my feature works

[sonarqubecloud]

Kudos, SonarCloud Quality Gate passed!   

0 Bugs
0 Vulnerabilities
0 Security Hotspots
0 Code Smells

No Coverage information
No Duplication information

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