third_party/py: update rules_python, use pip-compile for requirements

Change-Id: If8309e8e3a4b58142f7479005a9eb4cbb1043cdb
Reviewed-on: https://gerrit.hackerspace.pl/c/hscloud/+/1324
Reviewed-by: q3k <q3k@hackerspace.pl>
diff --git a/third_party/py/BUILD b/third_party/py/BUILD
index e69de29..eadbafd 100644
--- a/third_party/py/BUILD
+++ b/third_party/py/BUILD
@@ -0,0 +1,4 @@
+load("@rules_python//python:pip.bzl", "compile_pip_requirements")
+compile_pip_requirements(
+    name = "requirements",
+)