Simplify renovate configuration

[chris3ware]

Use the renovate security preset with custom parameters as required as opposed to full configuration.

See this link for the security preset:

https://docs.renovatebot.com/presets-security/

Suggested configuration:

{
  "$schema": "https://docs.renovatebot.com/renovate-schema.json",
  "commitMessageExtra": "",
  "commitMessageLowerCase": "never",
  "extends": ["security:only-security-updates"],
  "vulnerabilityAlerts": {
    "addLabels": ["security"],
    "commitMessagePrefix": "fix(deps): ",
    "rangeStrategy": "auto"
  }
}

This configuration uses the preset security update configuration, but remove the commit message suffix in favour of a label, allows upper case characters in the commit message and changes the prefix.