Children prop for SVG components#975

<!-- Love SVGR? Please consider supporting our collective: 👉 https://opencollective.com/svgr/donate --> ## 🚀 Feature Proposal When converting an SVG into a React component, allow `children` props so we can inject nodes into the rendered SVG element. ## Motivation Check the example bellow: ## Example Lets say I have an SVG with some `<symbol>` elements: ``` <svg xmlns="http://www.w3.org/2000/svg"> <symbol id="foo"><text>foo</text></symbol> <symbol id="bar"><text>bar</text></symbol> </svg> ``` Then I would be able to use like this: ```jsx import SvgSymbols from './symbols.svg'; export function Foo() { return ( <SvgSymbols> <use xlinkHref="#foo" /> </SvgSymbols> ); } export function Bar() { return ( <SvgSymbols> <use xlinkHref="#bar" /> </SvgSymbols> ); } ``` ## Pitch > Why does this feature belong in the SVGR ecosystem? It allows some level of customization on top of the static SVG component.