Megacheck found 2 small issues

[vaskoz]

honnef.co/go/tools/cmd/megacheck found 2 small issues:

sendgrid_test.go:23:2: var testAPIKey is unused (U1000)
sendgrid_test.go:165:5: should omit comparison to bool constant, can be simplified to !strings.Contains(err.Error(), "Client.Timeout exceeded while awaiting headers") (S1002)

This PR removes the unused variable and simplifies the boolean condition.

[thinkingserious]

Hello @vaskoz,

Thanks again for the PR!

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Team SendGrid DX

[mbernier]

Thanks @vaskoz!!