git: update config and add defaults for merging and rebasing

roles/git/defaults/main.yml

@@ -4,7 +4,13 @@ git_user: your-username
 git_email: your-email@example.com
 git_signkey:
 git_signingkey:
+
 git_do_sign: false
+git_merge_autostash: true
+git_rebase_autostash: true
+git_pull_rebase: true
+git_pull_ff_only: true
+git_default_branch: main
 
 git_user_home: "/home/{{ git_system_user }}"
 git_system_user: "{{ git_user }}"
@@ -15,3 +21,5 @@ git_gpg_program: ~
 git_aliases: []
 
 git_credentials: []
+
+git_config_preferred_editor: vim