⭐️New: Add vue/valid-v-bind-sync rule

[ota-meshi]

This PR add vue/valid-v-bind-sync rule. (#639)

vue/valid-v-bind-sync rule reports .sync modifier on v-bind directives in the following cases:

• The .sync modifier does not have the attribute value which is valid as LHS. E.g. <MyComponent v-bind:aaa.sync="foo() + bar()" />
• The .sync modifier is on non Vue-components. E.g. <input v-bind:aaa.sync="foo"></div>
• The .sync modifier's reference is iteration variables. E.g. <div v-for="x in list"><MyComponent v-bind:aaa.sync="x" /></div>

Close #639

[armano2]

can you add test for:

<template><svg><MyComponent :foo.sync="this.foo().bar" /></svg></template>

[ota-meshi]

@armano2 Thank you for your review!
I changed it. so please check agein.

[mysticatea]

LGTM, thank you!