task: remove outdated MessagePack reference

Author: mrdav30

.github/FUNDING.yml

@@ -0,0 +1,12 @@
+# These are supported funding model platforms
+
+github: # Replace with up to 4 GitHub Sponsors-enabled usernames e.g., [user1, user2]
+patreon: mrdav30
+open_collective: # Replace with a single Open Collective username
+ko_fi: mrdav30
+tidelift: # Replace with a single Tidelift platform-name/package-name e.g., npm/babel
+community_bridge: # Replace with a single Community Bridge project-name e.g., cloud-foundry
+liberapay: # Replace with a single Liberapay username
+issuehunt: # Replace with a single IssueHunt username
+otechie: # Replace with a single Otechie username
+custom: # Replace with a single custom sponsorship URL

Runtime/FixedMathSharp.Runtime.asmdef

@@ -1,9 +1,7 @@
 {
     "name": "FixedMathSharp.Runtime",
     "rootNamespace": "",
-    "references": [
-		"MessagePack"
-	],
+    "references": [],
     "includePlatforms": [],
     "excludePlatforms": [],
     "allowUnsafeCode": false,