Add: Protocol schema modification template

.gitlab/issue_templates/protocol_change.md

@@ -0,0 +1,42 @@
+## Protocol / API Change
+
+### Summary
+<!-- Brief description of the protocol change -->
+
+### Affected Commands / Responses
+<!-- Which commands or response types are being added, changed, or removed? -->
+
+| Command | Response | Type of Change | Description |
+|---------|----------|----------------|-------------|
+|         |          | New / Changed / Removed | |
+
+### New / Changed Syntax
+```
+<!-- Before / after or new command syntax here -->
+<!-- Example:
+BEFORE: LOGIN UNAME=<username> PASS=<password>
+AFTER:  LOGIN USERNAME=<username> PASSWORD=<password>
+-->
+```
+
+### Affected Implementation Layers
+<!-- Which components / classes need to be updated? -->
+- [ ] `Session`
+- [ ] `User` or `UserRegistry`
+- [ ] `Tokenizer` / `RequestTokenClassifier`
+- [ ] `ProtocolParser`
+- [ ] `CommandParserDispatcher` + corresponding `CommandParser`
+- [ ] `CommandHandler`
+- [ ] `Response` hierarchy
+- [ ] `GameEngine` or `GameState`
+- [ ] Client-side (create your own issue and create link)
+
+### Migration Strategy
+<!-- If breaking change: how will migration be handled? -->
+
+### Motivation
+<!-- Why is this protocol change necessary? -->
+
+/label ~protocol
+
+/label ~server