ISSUE-440: Impossible to install v0.3.0 because of zstd

[sijie]

Original Issue: apache#440

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Expected behavior

It should be possible to install the latest version.

Actual behavior

PR apache#385 conflicts with other libs depending on github.com/DataDog/zstd. In my project, zstd is a transient dependency of many other open source dependencies, and all the other ones are using github.com/DataDog/zstd. This leads to an installation error:

../../go/pkg/mod/github.com/apache/pulsar-client-go@v0.3.0/pulsar/internal/compression/zstd_cgo.go:27:2: case-insensitive import collision: "github.com/datadog/zstd" and "github.com/DataDog/zstd"

Downgrading to v0.2.0 fixes the issue on the short term.

Steps to reproduce

go get -u