docs release v1.9.2

Jun 18, 2020 Documentation docs v1.9.2

Add Azure Lighthouse delegation (https://github.com/giantswarm/docs/pull/532)
Adjust list line-height and overall appearance (https://github.com/giantswarm/docs/pull/534)
Document the gsctl GSCTL_AUTH_TOKEN environmental variable (https://github.com/giantswarm/docs/pull/537)
Document the gsctl list clusters --sort flag (https://github.com/giantswarm/docs/pull/538)

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