update contributing since beta split
update contributing since beta split

hashicorp/terraform-provider-google,terraform-providers/terraform-provider-google,ubschmidt2/terraform-provider-google,hashicorp/terraform-provider-google,ubschmidt2/terraform-provider-google,terraform-providers/terraform-provider-google,ubschmidt2/terraform-provider-google,terraform-providers/terraform-provider-google,hashicorp/terraform-provider-google,terraform-providers/terraform-provider-google,terraform-providers/terraform-provider-google,hashicorp/terraform-provider-google,ubschmidt2/terraform-provider-google