Fix JSON type for SELECT_SOFT_SERIAL_SPEED

[jakoschiko]

For the variable SELECT_SOFT_SERIAL_SPEED, the JSON definition in info_config.hjson doesn't match keyboard.jsonschema.

Description

If I define the variable SELECT_SOFT_SERIAL_SPEED in my keyboard firmware, the generated JSON is invalid. The validation against keyboard.jsonschema will fail. I seems that info_config.hjson doesn't match keyboard.jsonschema for this case.

☐ Running command: ['make', '-r', '-R', '-f', 'builddefs/build_keyboard.mk', 'KEYBOARD=epomaker/split65', 'KEYMAP=via', 'KEYBOARD_FILESAFE=epomaker_split65', 'TARGET=epomaker_split65_via', 'VERBOSE=true', 'COLOR=true', 'SILENT=false', 'QMK_BIN="qmk"']
☒ Invalid API data: epomaker/split65: split.serial.speed: '1' is not of type 'integer'
☒ Invalid API data: epomaker/split65: split.serial.speed: '1' is not of type 'integer'

The compile error only happened after migrating my keyboard firmware from a very old version of qmk_firmware to the most recent one.

qmk_firmware/data/schemas/keyboard.jsonschema

Lines 914 to 929 in b01ed7d

	"serial": {
	"type": "object",
	"additionalProperties": false,
	"properties": {
	"driver": {
	"type": "string",
	"enum": ["bitbang", "usart", "vendor"]
	},
	"pin": {"$ref": "./definitions.jsonschema#/mcu_pin"},
	"speed": {
	"type": "integer",
	"minimum": 0,
	"maximum": 5
	}
	}
	},

Types of Changes

• Core
• Bugfix
• New feature
• Enhancement/optimization
• Keyboard (addition or update)
• Keymap/layout (addition or update)
• Documentation

Issues Fixed or Closed by This PR

Checklist

• My code follows the code style of this project: C, Python
• I have read the PR Checklist document and have made the appropriate changes.
• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• I have read the CONTRIBUTING document.
• I have added tests to cover my changes.
• I have tested the changes and verified that they work and don't break anything (as well as I can manage).

[jakoschiko]

The needed to adjust the commit message, it was outdated.