Fix Jitpack import issue for UsbSerial dependency

[hwh97]

As a temporary workaround, I used import the latest successful build hash tag (7ad6c9f6) to fix the Jitpack import issue for the UsbSerial dependency.

Related issue: #118

[ChaseGuru]

This is worth merging. It should be a fact that anyone who doesn't have the prior working jitpack version of the dependency cached the plugin will not work as is and this change fixes that.

THOUGH, I probably prefer using this guy's fork:
felHR85/UsbSerial#375 (comment)

Since it seems to modernize a few things.

[berdroid]

Using the fix from this PR ea4eb8b results in an error for me:

"Artifact name must not be null!"

Adding

name = UsbSerial

to the artifact seems to fix that.

See also felHR85/UsbSerial#375 (comment)

[hwh97]

Using the fix from this PR ea4eb8b results in an error for me:

Weird, it works on my side, maybe it's a compatibility issue from Gradle.

But as @ChaseGuru said, it's better to use a fixed version. The cache build we use may be cleared at any time. I'm closing this PR and hope this issue can fixed soon. Thanks.