Update branch references after master -> main rename

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01KUhDLb7eGUBraFsnhBoRGm

Author: gdespirito

.github/workflows/ci.yml

@@ -2,7 +2,7 @@ name: CI
 
 on:
   push:
-    branches: [master]
+    branches: [main]
   pull_request:
 
 jobs:

src/compat.ts

@@ -24,7 +24,7 @@ function warnDeprecated(): void {
     warned = true;
     process.emitWarning(
       'The gps-tracking v1 API (gps.server(...), snake_case events) is deprecated and will be removed in v3. ' +
-        'See https://github.com/freshworkstudio/gps-tracking-nodejs/blob/master/MIGRATION.md',
+        'See https://github.com/freshworkstudio/gps-tracking-nodejs/blob/main/MIGRATION.md',
       'DeprecationWarning',
     );
   }