Fix typo in exceptions.dart

[alikhaleghi76]

Fixed a typo mistake in BuildStepCompletedException class in exceptions.dart

[google-cla]

Thanks for your pull request! It looks like this may be your first contribution to a Google open source project. Before we can look at your pull request, you'll need to sign a Contributor License Agreement (CLA).

View this failed invocation of the CLA check for more information.

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[jakemac53]

Thanks @alikhaleghi76, are you able to sign the CLA?

[alikhaleghi76]

Thanks @alikhaleghi76, are you able to sign the CLA?

You're welcome!
I signed it after the warning. There should be no problem now.

[jakemac53]

It looks like you have two different emails here - one that made the commit and a different one that you signed with - which is why it is still failing the CLA check. Can you sign again with the email that you used to create the commit?

[alikhaleghi76]

It looks like you have two different emails here - one that made the commit and a different one that you signed with - which is why it is still failing the CLA check. Can you sign again with the email that you used to create the commit?

Sorry, you are right.
It's ok now.