docs(issue template): add template for reporting missing type completion

.github/ISSUE_TEMPLATE/missing_type.md

@@ -0,0 +1,17 @@
+---
+name: Missing type definition
+about: Create a report to help us improve the type completion from the Hypixel API
+title: ''
+labels: missing-type
+assignees: ''
+
+---
+
+**Property missing type**
+Describe where the type is, this can be pointing to a file and line number under `src/types/Augmented` or included the API endpoint, and a snippet of the type missing from the augmented types. 
+
+**Describe the type**
+Describe the possible contents of this type (preferably in the format of a Typescript interface), include an example, or point to elsewhere the type is documented (for example, if it exists under a different property).
+
+**Additional context**
+Add any other context here.