Release v0.7.2

Minor improvements and bug fixes

- Fixed backup locations being fetched even when --backup flag is not used
- Backup remotes are now completely ignored during sync operations unless explicitly enabled

- Changed default config path to ~/.config/gitsyncer/config.json (with .json extension)
- Updated all documentation to reflect the new default config path
- Better separation of backup functionality - truly opt-in behavior

- If you have a config at ~/.config/gitsyncer/config, rename it to config.json
- Backup locations no longer show "Warning: Remote repository does not exist yet" messages