fix(gh): update git protocol to ssh

Switch gh CLI git_protocol from https to ssh. Add hosts.yml to
prettierignore since the file is managed by gh CLI.

.prettierignore

@@ -16,3 +16,4 @@ local/bin/antigen.zsh
 local/bin/asdf
 tools
 docs/plans
+config/gh/hosts.yml

config/gh/hosts.yml

@@ -1,6 +1,5 @@
----
 github.com:
-  git_protocol: https
-  users:
-    ivuorinen:
-  user: ivuorinen
+    git_protocol: ssh
+    users:
+        ivuorinen:
+    user: ivuorinen