chore(package): auto-format *.ts files (#1029)

This patch ensures `*.ts` files are run thru Prettier before allowing them to be commited to Git.

## Reviewer checks

**Required fields, to be filled out by PR reviewer(s)**
- [x] Follows the commit message policy, appropriate for next version
- [x] Has documentation updated, a DU ticket, or requires no documentation change
- [x] Includes new tests, or was unnecessary
- [x] Code is reviewed for security by: @JKODU

package.json

@@ -118,6 +118,10 @@
     "*.js": [
       "prettier --write",
       "git add"
+    ],
+    "*.ts": [
+      "prettier --write",
+      "git add"
     ]
   }
 }