ci: let renovate bot automerge all versions

Proposal: disable requiring approvals for MR's generated by renovate bot so renovate bot can automatically merge updates when pipeline succeeds. Merge all versions except for Major versions, which requires human intervention (or we can choose to auto upgrade major versions too because when the pipeline succeeds we are already sure that it works).

go.mod major rule was removed because this would stop renovate bot from creating MR's for golang major version upgrades as can be seen in the dependency dashboard: #1229 (closed)