CML v0.18.12

• Allow running cml pr create without files (#1263)
• Warn on pre-existing branch in cml pr create (#1254 by @magdapoppins)
• Default CML name change (#1265, iterative/terraform-provider-iterative#726)
• Misc test/framework updates
  • add a .nvmrc file to support using the intended Node.js version (#1257 by @magdapoppins)
  • replace workflow set-output => GITHUB_OUTPUT (#1259)
  • fix multi-line workflow output (#1267)
  • bump actions (#1260)
  • bump versions (#1268, #1266)