[15.0] remove magento extra

This requirement pulls suds-jurko and has been stalled since 2019
It is safer to remove it.

fulfilio/python-magento#30

15.0/extra_requirements.txt

@@ -1,3 +1,6 @@
+# See https://github.com/pypa/setuptools/issues/2787#issuecomment-922781810
+setuptools<58
+
 # Extra python dependencies
 algoliasearch==1.17.0
 Adyen==1.2.0
@@ -6,7 +9,6 @@ cerberus==1.2
 boto3==1.7.40
 factur-x==0.3
 invoice2data==0.2.74
-magento==3.0
 mailjet-rest==1.3.0
 openupgradelib==1.3.2
 paramiko==2.4.2