Create a new issue template

Fixes #1348

Signed-off-by: Jon Skeet <jonskeet@google.com>

Author: jskeet

.github/ISSUE_TEMPLATE/config.yml

@@ -0,0 +1 @@
+blank_issues_enabled: false

.github/ISSUE_TEMPLATE/issue.md

@@ -0,0 +1,21 @@
+---
+name: New issue
+about: 'Create a new issue'
+title: ''
+labels: ''
+assignees: ''
+
+---
+(Please remove the text below after reading it.)
+
+When filing an issue in this repository, please consider the following:
+
+- Is this:
+  - A feature request for a new form of integration etc?
+  - A report of a technical issue with the existing spec?
+  - A suggestion for improving the clarity of the existing spec (even if it's not "wrong" as such)?
+  - Something else?
+- Is there context behind your request that would be useful for readers to understand? (There's no need to go into huge amounts of detail, but a few sentences about the motivation can be really helpful.)
+- Do you know *roughly* what you'd expect a change to address this issue would look like? If so, it's useful to create a PR at the same time, linking to the issue. This doesn't need to be polished and ready to merge - it's just to help clarify roughly what you're considering.
+
+If the issue is requires discussion, it's really useful if you're able to attend the weekly working group meeting as described [here](https://github.com/cloudevents/spec/?tab=readme-ov-file#meeting-time). Often a discussion which would take multiple back-and-forth comments on an issue can be resolved with a few minutes of conversation. We understand the timing may not be convenient for everyone - please let us know if that's the case, and we can potentially arrange something with the most relevant group members at a more convenient time.