quickstart: Fix tracer URL (#279)

_i18n/en/_docs/quickstart.md

@@ -105,4 +105,4 @@ something along the lines of:
 That's nothing, though. The real magic happens when you start building your
 own tools using the Python API that [frida-trace][] is built on top of.
 
-[frida-trace]: https://github.com/frida/frida-tools/blob/master/frida_tools/tracer.py
+[frida-trace]: https://github.com/frida/frida-tools/blob/main/frida_tools/tracer.py