Add pull reconciliation defaults to GitHub lesson (010)

[jcoliver]

As of Git v2.27, there appears a message on pull:

hint: You have divergent branches and need to specify how to reconcile them. hint: You can do so by running one of the following commands sometime before hint: your next pull: hint: hint: git config pull.rebase false # merge hint: git config pull.rebase true # rebase hint: git config pull.ff only # fast-forward only hint: hint: You can replace "git config" with "git config --global" to set a default hint: preference for all repositories. You can also pass --rebase, --no-rebase, hint: or --ff-only on the command line to override the configured default per hint: invocation. fatal: Need to specify how to reconcile divergent branches.

Should add something to the lesson, maybe towards the end, that includes this message and how to fix it (probably just CLI and git config pull.rebase false).