Chore/go package

[mmeloni]

In order to properly include pb.proto in other .proto files

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This change is 

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[jarifibrahim]

Hey @mmeloni Thank you so much for the PR. Would this PR fix #1208 ?

[mmeloni]

@jarifibrahim I can try to test it. How I should do?

[jarifibrahim]

@mmeloni A simple test would be to import badger v1.6 and badger v2.0 in a single go program and try to run it.

It looks like the issue isn't fixed by your PR. I see the following error on master and your PR

panic: proto: duplicate enum registered: pb.ManifestChange_Operation

goroutine 1 [running]:
github.com/golang/protobuf/proto.RegisterEnum(...)
	/home/ibrahim/Projects/go/pkg/mod/github.com/golang/protobuf@v1.3.1/proto/properties.go:459
github.com/dgraph-io/badger/v2/pb.init.0()
	/home/ibrahim/Projects/go/pkg/mod/github.com/dgraph-io/badger/v2@v2.0.2/pb/pb.pb.go:638 +0x459
exit status 2

[jarifibrahim]

@mmeloni can you please add some information to the PR description about why this change is necessary? My understanding of protobufs is very limited. Thank you :)

[mmeloni]

Sure,
please take a look at https://developers.google.com/protocol-buffers/docs/reference/go-generated#package first.
In my case go_package was needed to correct import badger .proto types in another .proto file.

[jarifibrahim]

Thanks for the PR @mmeloni

Reviewed 1 of 1 files at r1.
Reviewable status: complete! all files reviewed, all discussions resolved (waiting on @ashish-goswami and @manishrjain)