deprecated api warning in already old 3js revision

[makc]

[EricTop3]

You can write one yourself, for example
let renderTarget = new THREE.WebGLRenderTargetCube(2048, 2048, {
format: THREE.RGBFormat,
magFilter: THREE.LinearFilter,
minFilter: THREE.LinearFilter
});
let cubeCamera = new THREE.CubeCamera(0.1, 1000, renderTarget);