change: make converted referenced pytest files always relative to project RootDir

tests/data/debugtalk.py

@@ -0,0 +1,13 @@
+from httprunner import __version__
+
+
+def get_httprunner_version():
+    return __version__
+
+
+def sum_two(m, n):
+    return m + n
+
+
+def get_variables():
+    return {"foo1": "session_bar1"}