Prepare release 0.3.0 (#537)

* Prepare release 0.3.0

Signed-off-by: Ruben Vargas <[email protected]>

* Remove obsolete changelog msg, updated formatting

Signed-off-by: Andreas Gerstmayr <[email protected]>

* Set operator version in Makefile

Workaround for the failing `ensure-generate-is-noop` test in CI.

Signed-off-by: Andreas Gerstmayr <[email protected]>

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Signed-off-by: Ruben Vargas <[email protected]>
Signed-off-by: Andreas Gerstmayr <[email protected]>
Co-authored-by: Andreas Gerstmayr <[email protected]>

Author: rubenvp8510