Update issue templates

adding a resource contribution template

.github/ISSUE_TEMPLATE/resource-contribution.md

@@ -0,0 +1,16 @@
+---
+name: Resource contribution
+about: Contribute an existing TADS 3 resource
+title: "[RESOURCE]"
+labels: ''
+assignees: ''
+
+---
+
+```yaml
+- title: [the name of the resource]
+  type: [the type/category of resource (TADS 3 language, Adv3, adv3Lite, for beginners). a resource can be multiple types]
+  author: [the main creator of the resource]
+  description: [what is the resource? who is it for? why is it useful?]
+  url: [link to the resource]
+```