Bump xml2js, gatsby-plugin-sharp and gatsby-transformer-sharp (#78)

Removes [xml2js](https://github.com/Leonidas-from-XIV/node-xml2js). It's no longer used after updating ancestor dependencies [xml2js](https://github.com/Leonidas-from-XIV/node-xml2js), [gatsby-plugin-sharp](https://github.com/gatsbyjs/gatsby/tree/HEAD/packages/gatsby-plugin-sharp) and [gatsby-transformer-sharp](https://github.com/gatsbyjs/gatsby/tree/HEAD/packages/gatsby-transformer-sharp). These dependencies need to be updated together.


Removes `xml2js`

Updates `gatsby-plugin-sharp` from 4.11.1 to 4.25.1
- [Release notes](https://github.com/gatsbyjs/gatsby/releases)
- [Changelog](https://github.com/gatsbyjs/gatsby/blob/master/packages/gatsby-plugin-sharp/CHANGELOG.md)
- [Commits](https://github.com/gatsbyjs/gatsby/commits/gatsby-plugin-sharp@4.25.1/packages/gatsby-plugin-sharp)

Updates `gatsby-transformer-sharp` from 4.11.0 to 4.25.0
- [Release notes](https://github.com/gatsbyjs/gatsby/releases)
- [Changelog](https://github.com/gatsbyjs/gatsby/blob/master/packages/gatsby-transformer-sharp/CHANGELOG.md)
- [Commits](https://github.com/gatsbyjs/gatsby/commits/gatsby-transformer-sharp@4.25.0/packages/gatsby-transformer-sharp)

---
updated-dependencies:
- dependency-name: xml2js
  dependency-type: indirect
- dependency-name: gatsby-plugin-sharp
  dependency-type: direct:production
- dependency-name: gatsby-transformer-sharp
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>