docs(samples): correct publish retry settings

[anguillanneuf]

• corrected retryCodes to a list of Google API canonical error codes
• corrected backOffSettings to default values specified in src/v1/publisher_client_config.json

ref: https://googleapis.github.io/gax-nodejs/gax.js.html

[jkwlui]

@stephenplusplus @callmehiphop need a closer look into this one. Had a look at gax-nodejs but I wasn’t familiar enough to determine whether retry parameter is supplied the way it should be.

[callmehiphop]

@kinwa91 If we're just supplying the default retry options for publishing, then these definitely match what is listed in the publisher_client_config.json. I'm concerned that these could become out of sync in the future if the config json is regenerated with tweaked values.

[anguillanneuf]

@kinwa91 The sample should be ready to be merged now. Thanks!