`rgba()` value after minify will get a `0.002` increase in its alpha value

[haoqunjiang]

Reproduction

echo "div { color: rgba(100, 100, 100, 0.5); }\n" | esbuild --minify --loader=css --target=chrome61

Output

div{color:rgba(100,100,100,.502)}

Expected output

div{color:rgba(100,100,100,.5)}

[evanw]

These fractions are equivalent since there are only 256 underlying discrete alpha values, but esbuild should obviously use the shortest numeric representation here. I'll fix this.