ETL-447: add update method to pipeline

[PabloPardoGarcia]

Add update method to pipeline objects. Now users can update pipelines as follows:

from glassflow.etl import Client

client = Client(host="myglassflow.com")

pipeline = client.get_pipeline("my-pipeline-id")

# Pass dictionary with update patch (or full new pipeline config)
pipeline.update({
    "sink": {
        "host": "new-host", 
        "username": "new-user", 
        "password": "new-password"
    }
})

[github-actions]

Test Coverage Report

File	Stmts	Miss	Cover	Missing
etl
__init__.py	5	0	100%
api_client.py	64	5	92%	70–73, 123
client.py	39	4	89%	59–61, 141
dlq.py	41	2	95%	45, 70
errors.py	27	0	100%
pipeline.py	145	7	95%	334–337, 350, 405–406
tracking.py	26	0	100%
etl/models
__init__.py	7	0	100%
base.py	10	1	90%	10
config.py	34	8	76%	37, 40–41, 43–45, 47–48
data_types.py	77	0	100%
join.py	51	2	96%	44, 80
pipeline.py	124	9	92%	68, 73, 77, 93, 112, 134, 153, 166, 174
sink.py	71	7	90%	42, 48, 56, 58, 62, 64, 72
source.py	155	9	94%	60, 64, 81, 94, 128, 133, 171, 197, 213
TOTAL	876	54	93%