Updated paystack api for enable/disable subscriptions

[Daskott]

Current Behaviour

• Calling disable/enable function on subscription times out because the api end-points are out-dated

New Behaviour

• Api end-points to disable/enable subscriptions has been updated and now returns the appropriate response

[Daskott]

• The build is currently failing because it does not have access to paystack secret-key @kehers is there a way to address this? Thanks
• Also tests for my change are already in the subscription test file but commented out, probably because there's no email token & subscription code to test it.

[TejasParse]

Disable subscription is not working currently. Any way to make it work?