Bump @types/proj4 from 2.5.5 to 2.5.6

Bumps [@types/proj4](https://github.com/DefinitelyTyped/DefinitelyTyped/tree/HEAD/types/proj4) from 2.5.5 to 2.5.6.
- [Release notes](https://github.com/DefinitelyTyped/DefinitelyTyped/releases)
- [Commits](https://github.com/DefinitelyTyped/DefinitelyTyped/commits/HEAD/types/proj4)

---
updated-dependencies:
- dependency-name: "@types/proj4"
  dependency-type: direct:development
  update-type: version-update:semver-patch
...

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Author: dependabot[bot]