CompatHelper: bump compat for "POMDPs" to "0.9"

[github-actions[bot]]

This pull request changes the compat entry for the POMDPs package from 0.7.3, 0.8 to 0.7.3, 0.8, 0.9.

This keeps the compat entries for earlier versions.

Note: I have not tested your package with this new compat entry. It is your responsibility to make sure that your package tests pass before you merge this pull request.

[codecov[bot]]

Codecov Report

Merging #38 into master will not change coverage. The diff coverage is n/a.

@@           Coverage Diff           @@
##           master      #38   +/-   ##
=======================================
  Coverage   97.77%   97.77%           
=======================================
  Files           4        4           
  Lines         135      135           
=======================================
  Hits          132      132           
  Misses          3        3           

---

Continue to review full report at Codecov.

Legend - Click here to learn more Δ = absolute <relative> (impact), ø = not affected, ? = missing data Powered by Codecov. Last update 356a4d2...918f51e. Read the comment docs.

[zsunberg]

already done