update clone urls INSTALL.md

[jaelynlitz]

Merge request type

• [ ] New feature
• [ ] Resolves bug
• [X] Documentation
• [ ] Other

Relates to

• [ ] OPFLOW
• [ ] SOPFLOW
• [ ] SCOPFLOW
• [ ] TCOPFLOW
• [ ] CMake build system
• [ ] Spack configuration
• [ ] Manual
• [X] Web docs
• [ ] Other

This MR updates

• [ ] Header files
• [ ] Source code
• [ ] CMake build system
• [ ] Spack configuration
• [X] Web docs
• [ ] Manual
• [ ] Other

Summary

fix code block links to use the github instead of gitlab

Linked Issue(s)

closes #116

[jaelynlitz]

probably need to add git submodule update --init --recursive to our instructions

[cameronrutherford]

LGTM - going to merge even though CI is failing since this is just cosmetic