will git stop being weird (#29897)

(cherry picked from commit 57c131d)

Author: LB

packages/gatsby-transformer-sharp/src/customize-schema.js

@@ -453,7 +453,6 @@ const imageNodeType = ({
         not know the formats of the source images, as this could lead to unwanted results such as converting JPEGs to PNGs. Specifying 
         both PNG and JPG is not supported and will be ignored.
         `,
-        defaultValue: [`auto`, `webp`],
       },
       outputPixelDensities: {
         type: GraphQLList(GraphQLFloat),