UnhandledPromiseRejectionWarning when "svgSprites" is enabled

[clemensf]

in a project, we have svg icons in /src/resources/icons/ and they are converted to an iconfont with task "iconfont".

However if the task "svgSprites" is also enabled (which is the default), we get many warnings like this:

"(node:48413) UnhandledPromiseRejectionWarning (node:48413) UnhandledPromiseRejectionWarning: Unhandled promise rejection. This error originated either by throwing inside of an async function without a catch block, or by rejecting a promise which was not handled with .catch(). (rejection id: 2) (node:48413) UnhandledPromiseRejectionWarning"