Bump pyfcm from 1.5.4 to 2.0.6

Bumps [pyfcm](https://github.com/olucurious/pyfcm) from 1.5.4 to 2.0.6.
- [Release notes](https://github.com/olucurious/pyfcm/releases)
- [Changelog](https://github.com/olucurious/PyFCM/blob/master/CHANGES.rst)
- [Commits](olucurious/PyFCM@1.5.4...2.0.6)

---
updated-dependencies:
- dependency-name: pyfcm
  dependency-type: direct:production
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <[email protected]>