X deaactivate pyproject.toml for now

there is no golang.pyx.build.build_ext in pygolang 0.0.4 and due to that
wendelin.core build fails, even though if pygolang@master version is
installed locally.

pyproject.toml

-[build-system]
-requires = ["pygolang[pyx.build] >= 0.0.5"]
+# TODO reenable once pygolang 0.0.5 is released
+#[build-system]
+#requires = ["pygolang[pyx.build] >= 0.0.5"]