rgb()/rgba() CSS color values not supported in filterCssValue

[oujesky]

I am running into following error when using rgb(...) or rgba(...) in CSS color values with strict autoescaping.

Uncaught AssertionError: Failure: Bad value rgba(0,0,0,0.6) for |filterCssValue

Testing template:

{namespace test}

{template .item}
    {@param? style: [color: string]}

    <div style="{call .style}{param style: $style /}{/call}">
        test
    </div>
{/template}

{template .style private="true" kind="css"}
    {@param? style: [color: string]}

    {if $style.color}background-color: {$style.color};{/if}
{/template}

To reproduce, it can be called with following JS code:

test.item({
    style = {
        color: 'rgba(0, 0, 0, 0.6)'
    }
}); 

The culprit seems to be this regular expression and in turn this generated JS code.

I can supply PR if interested.