[alertmanager] Fixing "cannot overwrite table with non table" warning (…

…prometheus-community#3245)

* Fixing "cannot overwrite table with non table" warning

Signed-off-by: Aaron Layfield <aaron.layfield@gmail.com>

* Correct type at dnsConfig

Signed-off-by: zeritti <47476160+zeritti@users.noreply.github.com>

* Update Chart.yaml

Signed-off-by: Quentin Bisson <quentin.bisson@gmail.com>

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Signed-off-by: Aaron Layfield <aaron.layfield@gmail.com>
Signed-off-by: zeritti <47476160+zeritti@users.noreply.github.com>
Signed-off-by: Quentin Bisson <quentin@giantswarm.io>
Signed-off-by: Quentin Bisson <quentin.bisson@gmail.com>
Co-authored-by: zeritti <47476160+zeritti@users.noreply.github.com>
Co-authored-by: Quentin Bisson <quentin@giantswarm.io>
Co-authored-by: Quentin Bisson <quentin.bisson@gmail.com>
Co-authored-by: André Bauer <monotek@users.noreply.github.com>