fix: snapshots failing because of wrong mysql colum quoting

[outinim]

Description

When I do snapshots on a table on which i add columns: it use the function (if I read correctly the file dbt/include/mariadb/macros/materializations/snapshot/snapshot.sql) {% do create_columns(target_relation, missing_columns) %} which compiles into (for my source table users with a new column team) into alter tablesandbox.users_snapshotadd column "team" varchar(10); But it needs to be add column team to work in mysql

Checklist

• [ ] I have run this code in development and it appears to resolve the stated issue
• [ ] This PR includes tests, or tests are not required/relevant for this PR
• [ ] I have updated the CHANGELOG.md with information about my change

[outinim]

Something like this is better ? Thanks for the reviews guys

[mwallace582]

Sorry for the delay in taking a look at your changes. This is looking a lot better, and I've just got the one new comment.

It'd also be great if you'd be able to add some tests around this, although I'd be willing to merge this without them given the small scope of the changes.