Fix bugs related to go_version_file input

[upamune]

WHAT

1. Added go_version_file to action.yml to avoid a warning
2. Remove the default value of go_version from action.yml and add the deafult Go version to the code.

WHY

1. To avoid a below warning

Warning: Unexpected input(s) 'go_version_file', valid inputs are ['github_token', 'golangci_lint_flags', 'tool_name', 'level', 'reporter', 'filter_mode', 'fail_on_error', 'reviewdog_flags', 'workdir', 'reviewdog_version', 'golangci_lint_version', 'go_version', 'cache']

2. If the go_version default value is set in action.yml, the go_version_file value is never used. This is because if both are set, the go_version value takes precedence. Therefore, I've modified it to use the default version if go_version and go_version_file are not set.

[upamune]

@shogo82148 Thank you for reviewing the #389. I actually tried to run it, but found problems. Therefore, I created this PR. Could you review it?

[upamune]

When a user wants to use the default goVersion, the goVersion is passed as an empty string, so I removed this if block.

[shogo82148]

LGT

[upamune]

Thank you for your quick review! I tried the following pattern on my project and confirmed that it works correctly.

• specify only go_version
• specify only go_version_file
• specify both go_version and go_version_file
• specify nothing