Example 1 - By name
Color = "Red";
Example 2 - By id
customfield_12345 = "Blue";
Example 3 - By alias
productColor = "Green";
NOTE: This script assumes that it is running in the context of an issue. Like in a
workflow script or listener for example. If you would like to test this script
from the SIL Manager, add an issue key to test with under the Run Configuration
setting (Run > Run Configuration > Context).