Create a method to checkpoint a run

[hansende]

Create a Python Method in the existing FlowMetr Python class to checkpoint a run for a flow, which can be called like:

flow1.checkpoint(node_id="checkpoint-1", run_id="my first run", logs="Called Support Agent")

logs: optional

The method will create a http get call like

https://flowmetr.com/hooks/339a7c52-58eb-4537-ab92-9a57f0bae96b?run_id=2af8344d284bb641&node_id=checkpoint-1&node_type=checkpoint&logs=Checkpoint1&project_token=f815f37293f415e33e3b8542cc6eefa433809e1777774632f2343668792f3dd1

the method has to set the node_type "checkpoint"

Test:

Can be tested locally with FlowMetr started through docker
compose or with flow in Flowmetr Cloud.

When successful a previously started flow gets a checkpoint after calling the method, which can be watched in the related public dashboard:
https://flowmetr.com/public/projects/f0cf4767cd9c42f2713954c1ea9cc097b31488b6