Build linux-debian10 (Jun 5, 2021, 7:53:08 AM)

1. update to 5.7.2 (details / githubweb)
2. update submodules (details / githubweb)
3. update fmt submodule (details / githubweb)
4. fix build with latest fmt::format updates (details / githubweb)
5. update mybasic submodule (details / githubweb)

Started by upstream project wwiv build number 3533
originally caused by:

• Started by an SCM change

• refs/remotes/origin/main