Update replace deprecated use of getfuncargvalue to please new pytest versions

tests/pfwtest.py

@@ -51,7 +51,7 @@ def check_injected_python_installed(request):
     if len(procparams) != 1:
         raise ValueError("Could not find the fixture name of the injected python")
     procparam = procparams[0]
-    proc = request.getfuncargvalue(procparam)
+    proc = request.getfixturevalue(procparam)
     if not python_is_installed[proc.bitness]:
         pytest.skip("Python {0}b not installed -> skipping test with python injection into {0}b process".format(proc.bitness))
     return None