Warns in VScode about commits to master (#81908)

## About The Pull Request

If you're jim the new dev and you're using vscode to make commits to
master, let's add a "what's this" message for you before you do so
accidentially.


## Why It's Good For The Game

Should hopefully save some heartache for people who do not yet know how
branches work

.vscode/settings.json

@@ -13,6 +13,7 @@
 	},
 	"files.eol": "\n",
 	"files.insertFinalNewline": true,
+	"git.branchProtection": ["master"],
 	"gitlens.advanced.blame.customArguments": ["-w"],
 	"tgstationTestExplorer.project.resultsType": "json",
 	"[javascript]": {