doc: bumpFiles key for file path is not valid

[antkaz]

When I updated the package to version 7.1.0 and added to config

"bumpFiles": [
  {
    "file": "path/to/file.jsom",
    "type": "json"
  }
],

I get error Path must be a string. Received undefined. But when I changed file key to filename, then script is work

[coveralls]

Coverage remained the same at 99.429% when pulling 16d3390 on antkaz:patch-1 into cd227ea on conventional-changelog:master.

[tommywo]

@antkaz Thank you for your contribution. 👍