Update matching-pattern in debian/watch

so that it would match, for example, v0.43.0 instead of logging/v1.0.0.
See https://code-review.googlesource.com/c/gocloud/+/41530
1 job for master in 2 minutes and 9 seconds (queued for 3 seconds)
latest
Status Job ID Name Coverage
  Test
passed #250311
test_the_archive

00:02:09