`xpkg init provider-template-upjet` does not result in a buildable repo about crossplane

[jbw976]

Note this scenario works when using just a regular git clone followed by a make. The build submodule gets synced and make has targets to execute on successfully:

❯ git clone https://github.com/crossplane/upjet-provider-template.git
Cloning into 'upjet-provider-template'...
remote: Enumerating objects: 1480, done.
remote: Counting objects: 100% (331/331), done.
remote: Compressing objects: 100% (87/87), done.
remote: Total 1480 (delta 277), reused 259 (delta 244), pack-reused 1149
Receiving objects: 100% (1480/1480), 469.91 KiB | 2.41 MiB/s, done.
Resolving deltas: 100% (750/750), done.

❯ cd upjet-provider-template

❯ make
Submodule 'build' (https://github.com/crossplane/build) registered for path 'build'
Cloning into '/Users/jared/Desktop/crossplane/upjet-provider-template/build'...
Submodule path 'build': checked out 'b0dfb8fbe8c626e3e0f0b6efdfac926d750adf48'
Initial setup complete. Running make again . . .
10:19:15 [ .. ] installing up v0.18.0
10:19:18 [ OK ] installing up v0.18.0
10:19:19 [ .. ] go build linux_arm64
k8s.io/apimachinery/pkg/selection
golang.org/x/exp/maps
k8s.io/apimachinery/pkg/types
google.golang.org/protobuf/internal/flags
(continues so on and so forth...)