Chore: update default config.json

[Amia33]

TL;DR We should give some default value directly in the config.json generated for the first time to avoid problems

1 ERROR: Failed to parse response (but not fatal)

EDIT: This issue seems not persistent across platforms, so runtime reports are welcomed!

Multi-line json file will introduce error when running the software. (I use vscode's built-in feature for better reading experience.)

ERROR: Failed to parse response:
%!(EXTRA *json.UnmarshalTypeError=json: cannot unmarshal object into Go value of type []main.Tag)

However those scores can still be updated, so this is a low-priority issue.

~~2 Default value for addr seems not fine~~ Resolved in v1.3.3

Following config works:

{
    "username": "some_username",
    "password": "some_password",
    "slice": true,
    "timeout": 120,
    "mai_diffs": [
        "exp",
        "mas",
        "rem"
    ],
    "addr": "127.0.0.1:8033"  //EDIT: ":8033" also works
}

INFO: 代理设置已自动修改。
INFO: 代理已开启到 127.0.0.1:8033

While this config doesn't:

{
    "username": "some_username",
    "password": "some_password",
    "slice": true,
    "timeout": 120,
    "mai_diffs": [
        "exp",
        "mas",
        "rem"
    ]
}

WARN: 自动修改代理设置失败。请尝试手动修改代理。
INFO: 代理已开启到

Seems that default value for addr is not exist.