Unable to add app if config repo is public

[J-Thompson12]

Describe the bug
Unable to add gitlab or github app if the config repo is public.
Error for public repo:

"error":"unable to clone 'ssh://git@gitlab.com/gogittest/sub-group/test-app-t75anmiy.git': ssh: handshake failed: ssh: unable to authenticate, attempted methods [none publickey] │
│ , no supported methods remain"}  

Environment

• gitops: [e.g. v0.1.0]
• kubernetes: [e.g. 1.20.4]
  • KinD - version]
  • k3s - version
  • cloud [e.g., EKS, AKS] version
  • other - name version
• Browser + version: [e.g. chrome 74, safari 12, firefox 87]

Affects versions

To Reproduce
Steps to reproduce the behavior:

1. Start with fresh env
2. Install gitops using public config repo
3. Run gitops add app . --config-repo=<repo>
4. See error

Expected behavior
The app to add and reconcile properly.

Additional context

[J-Thompson12]

The changes made in #1249 made it so that without a deploy key we are unable to clone the repo. Install without auto-merge does not clone it just creates a PR and then add always clones so it fails. Install with auto-merge clones the repo so it fails to install.

[J-Thompson12]

Possible solutions:

1. Force users to use private repos for config repo
2. Use go-git-providers for auto-merge to avoid cloning.
3. Remove changes to only using deploy key on private.
4. A solution I dont know of that magically fixes all our problems.