testing/shfmt: Mark go only as a compiletime dependency

Go shouldn't be required to run the application, it is a statically
compiled binary after all. Mark go only as a compile time dependency.

Signed-off-by: Olliver Schinagl <oliver@schinagl.nl>
7 jobs for !630 with shfmt in 10 minutes and 22 seconds (queued for 2 seconds)
detached
Status Job ID Name Coverage
  Lint
passed #6647
docker-alpine x86_64
lint

00:01:57

 
  Build
passed #6652
docker-alpine ci-build aarch64
build-aarch64

00:02:54

passed #6653
docker-alpine ci-build armv7
build-armv7

00:03:18

passed #6651
docker-alpine ci-build ppc64le
build-ppc64le

00:02:51

passed #6650
docker-alpine ci-build s390x
build-s390x

00:01:43

passed #6649
docker-alpine ci-build x86
build-x86

00:02:07

passed #6648
docker-alpine ci-build x86_64
build-x86_64

00:01:55