prefer-template in template

[SimacIDS]

Please describe what the rule should do:

The rule should have the template comply to the following rule: https://eslint.org/docs/rules/prefer-template
Currently when using this rule template-strings are not enforced inside the template

What category should the rule belong to?

• Enforces code style
• Warns about a potential error
• Suggests an alternate way of doing something
• Other (please specify:)

Provide 2-3 code examples that this rule should warn about:

<template>
    <div class="options">
        <button v-for="option in options" 
                      :class="'btn btn-' + option.style"
        >
            {{ option.text }}
        </button>
    </div>
</template>

<template>
    <h3 :style="'color:' + preferredTitleColor + '; font-size:' + preferredFontSize + ';'">
        Welcome
    <h3/>
</template>

Additional context

Nope

[ota-meshi]

I have implemented this rule. #1141
I plan to alpha release this weekend.