pythonPackages.proto-plus: init at 1.10.1

I am adding this package because it is a dependency of
google_cloud_dataproc.

pkgs/development/python-modules/proto-plus/default.nix

@@ -0,0 +1,24 @@
+{ stdenv
+, buildPythonPackage
+, fetchPypi
+, protobuf
+}:
+
+buildPythonPackage rec {
+  pname = "proto-plus";
+  version = "1.10.1";
+
+  src = fetchPypi {
+    inherit pname version;
+    sha256 = "0n8ia51jg2dkab2sf0qnh39bssqhz65ybcqr78f3zzf7ja923lkr";
+  };
+
+  propagatedBuildInputs = [ protobuf ];
+
+  meta = with stdenv.lib; {
+    description = "Beautiful, idiomatic protocol buffers in Python";
+    homepage = "https://github.com/googleapis/proto-plus-python";
+    license = licenses.asl20;
+    maintainers = [ maintainers.ruuda ];
+  };
+}

pkgs/top-level/python-packages.nix

@@ -4665,6 +4665,8 @@ in {
 
   protego = callPackage ../development/python-modules/protego { };
 
+  proto-plus = callPackage ../development/python-modules/proto-plus { };
+
   protobuf = callPackage ../development/python-modules/protobuf {
     disabled = isPyPy;
     doCheck =