warning: a secret was passed to "sh" using groovy string interpolation, which is insecure.
It is for Security purpose.
If Groovy performs the interpolation,
the sensitive value will be injected directly
into the arguments of the 'sh' step,
which among other issues, means that the literal value
will be visible as an argument to the sh process on the agent in OS process listings.
Using single quotes instead of double quotes when referencing
these sensitive environment variables prevents this type of leaking.