CompatHelper: bump compat for "Juno" to "0.8"

[github-actions]

This pull request changes the compat entry for the Juno package from 0.7 to 0.7, 0.8.

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-io]

Codecov Report

❗ No coverage uploaded for pull request base (master@0e92b76). Click here to learn what that means.
The diff coverage is n/a.

@@            Coverage Diff            @@
##             master    #1399   +/-   ##
=========================================
  Coverage          ?   90.31%           
=========================================
  Files             ?       39           
  Lines             ?     4242           
  Branches          ?        0           
=========================================
  Hits              ?     3831           
  Misses            ?      411           
  Partials          ?        0

---

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 0e92b76...9f1e9b3. Read the comment docs.