add clightning python pkgs

pkgs/python-packages/pyln-proto/default.nix

@@ -0,0 +1,31 @@
+{ buildPythonPackage, clightning
+, bitstring
+, cryptography
+, coincurve
+, base58
+, mypy
+}:
+
+buildPythonPackage rec {
+  pname = "pyln-proto";
+  version = "0.8.4"; # defined in ${src}/contrib/pyln-proto/setup.py
+
+  inherit (clightning) src;
+
+  propagatedBuildInputs = [
+    bitstring
+    cryptography
+    coincurve
+    base58
+    mypy
+  ];
+
+  postUnpack = "sourceRoot=$sourceRoot/contrib/${pname}";
+
+  postPatch = ''
+    substituteInPlace requirements.txt \
+      --replace base58==1.0.2 base58==2.0.1 \
+      --replace bitstring==3.1.6 bitstring==3.1.5 \
+      --replace cryptography==2.8 cryptography==3.1
+  '';
+}