semantic validation a github url will cause JSON_PARSING_ERROR

[ankhyk]

when running oav validate-spec (a github url for the spec path), it will report JSON_PARSING_ERROR

for example:

oav validate-spec https://github.com/Azure/autorest.testserver/blob/main/swagger/azure-special-properties.json
Semantically validating https://github.com/Azure/autorest.testserver/blob/main/swagger/azure-special-properties.json

Errors reported:

code: JSON_PARSING_ERROR
message: 'Json parsing error: invalid symbol'
position:
  line: 7
  column: 1
url: >-
  https://github.com/Azure/autorest.testserver/blob/main/swagger/azure-special-properties.json