fix: don't set AWS profile when role chaining (#841)

Fixes #555

This is a crude attempt to the fix the issue by overwritting the profile
name when the chain flag is passed.  This is set at the end, right
before returning the values to the shell, the only functionality
difference should be that that the `AWS_PROFILE` environment variable
will not be set when the `--chain` flag is passed.

Author: raine-tingley

pkg/assume/assume.go

@@ -519,6 +519,12 @@ func AssumeCommand(c *cli.Context) error {
 			return nil
 		}
 
+		//  When using the `--chain` flag, the profile does not exist because it is an ARN we are assuming, not a profile generated by granted.
+		//  Since the profile does not exist, the awscli will error due to it attempting to use a non-existent profile.
+		if assumeFlags.String("chain") != "" {
+			profile.Name = "None"
+		}
+
 		output := PrepareStringsForShellScript([]string{creds.AccessKeyID, creds.SecretAccessKey, creds.SessionToken, profile.Name, region, sessionExpiration, "false", "", "", "", "", ""})
 		fmt.Printf("GrantedAssume %s %s %s %s %s %s %s %s %s %s %s %s", output...)
 	}