Will be fixed in pending 1.13 release.

One would also have to replace all invocations of DyeColor.valueOf(String), since a plugin might previously used the name and Enum#valueOf for de/serialization purposes and Enum#valueOf cannot be overridden.

Also, now we have that bytecode transformation for plugins that were written for older version, so it's possible to just replace enum name on load for them.

Then, I suggest adding a method something like a getBlockColor(). I'm currently using this code below to get colored blocks (glass is just for an example) and DyeColor.SILVER is the only thing that does not match colors in the game.
If there already exists an API for this, then this new feature is not needed (but anyway, it would be nice).

public static Material getGlassByColor(DyeColor color) {
    return Material.getMaterial((color.equals(DyeColor.SILVER) ? "LIGHT_GRAY" : color.toString()) + "_STAINED_GLASS");
}

I thought more DyeColors were renamed than just this one (probably because the tropical fish in the mcwiki have different colour names).

Just the one probably makes the change slightly more approachable, it looks like the only thing that needs updating is banner patterns.

It's a big breaking change.

It'd need full compatibility for the enum values, ordinals, and fields, as well as serialized data.
I mean if you want to implement and test all that, sure; but seems like a lot of work for SILVER vs LIGHT_GRAY