ci: fix requirements.txt not found in src during building

Author: FlysonBot

setup.py

@@ -1,8 +1,9 @@
+import os
 from setuptools import find_packages, setup
 
 
-def read_requirements(file):
-    with open(file, "r") as f:
+def read_requirements(filename):
+    with open(os.path.join(os.path.dirname(__file__), filename), "r") as f:
         return [line.strip() for line in f if line and not line.startswith("#")]