Custom property values do not support hyphens

[bambro]

Description:
This issue extends from issue #40 to support hyphens in the custom property value, similar to the support that was added in for the key.

Currently the regex only supports alphanumeric characters and underscores with the following regex /^[a-zA-Z0-9](\w|_){1,128}$ and should be extended to /^[a-zA-Z0-9](\w|-|_){1,128}$.

Additional Information:

• Terraform Provider Version: v2.0.5
• Relevant Snippet:
  

  terraform-provider-synthetics/synthetics/resource_api_check_v2.go

  Line 211 in 3d51d05

  ValidateFunc: validation.StringMatch(regexp.MustCompile(`^[a-zA-Z0-9](\w|_){1,128}$`), "custom_properties value can only consist of alphanumeric and underscore characters with no whitespace"),

[greatestusername-splunk]

Good catch! Thought the hyphen had gotten into all of them in 40!
Are you at all interested in contributing a quick PR?