add Pipfile and pub-sub examples

Pipfile

+[[source]]
+url = "https://pypi.org/simple"
+verify_ssl = true
+name = "pypi"
+
+[packages]
+pyzmq = "*"
+
+[dev-packages]
+
+[requires]
+python_version = "3.8"
+python_full_version = "3.8.12"

pub-sub/publisher.py

+import signal
+import time
+import zmq
+
+
+signal.signal(signal.SIGINT, signal.SIG_DFL)
+
+context = zmq.Context()
+socket = context.socket(zmq.PUB)
+socket.bind('tcp://*:5555')
+
+for i in range(5):
+    socket.send(b'status 5')
+    socket.send(b'All is well')
+    time.sleep(1)

pub-sub/subscriber.py

+import signal
+import zmq
+
+
+signal.signal(signal.SIGINT, signal.SIG_DFL)
+
+context = zmq.Context()
+
+socket = context.socket(zmq.SUB)
+socket.connect('tcp://localhost:5555')
+socket.setsockopt(zmq.SUBSCRIBE, b'status')
+
+while True:
+    message = socket.recv_multipart()
+    print(f'Received: {message}')