Remove redundant go fmt/mod-vendor/mod-tidy

This script was running `go fmt` over the `yaml.v2` package as well.
That code is manually vendored and should not be changed, incidentally.

Note that this script runs ./hack/build.sh.
That script runs `go fmt` _excluding_ the `yaml.v2` package.
It also runs the `go mod...` commands removed here.

When Go is upgraded, sometimes this means that `go fmt` produces
different output. It does for Go 1.19.

Fixes: https://github.com/vmware-tanzu/carvel-ytt/actions/runs/3625263105

hack/build-binaries.sh

@@ -8,10 +8,6 @@ function get_latest_git_tag {
 
 VERSION="${1:-`get_latest_git_tag`}"
 
-go fmt ./cmd/... ./pkg/... ./test/...
-go mod vendor
-go mod tidy
-
 # makes builds reproducible
 export CGO_ENABLED=0
 LDFLAGS="-X github.com/vmware-tanzu/carvel-ytt/pkg/version.Version=$VERSION"