(0.8 series) ghc 8.6.5 support

[swamp-agr]

Adding support for GHC 8.6.5 into 0.8-series branch.

Looks like it's hard to pass cabal errors due to known issue with transformers: https://gitlab.haskell.org/ghc/ghc/issues/16199. Seems to be resolved in 8.8.1-alpha and actually some hotfix was applied in 8.6.5.

• v1- flow (see below) passed.

cabal v1-build
cabal v1-install
cabal v1-test

• v2- flow (see below) also passed.

cabal v2-build --enable-tests
cabal v2-install --symlink-bindir=$HOME/.local/bin
cabal v2-test

The only topic I am worrying about is Gitlab pipeline. I have not previously experienced with this Gitlab and its CI/CD capabilities. @DanielG, could you please suggest, is it necessary for this PR?

[swamp-agr]

Should close #62.

[DanielG]

Looks like you missed the commits on the gitlab-ci-0.8 branch. However it does appear that Cabal-2.2 is now out of bounds for GHC 8.6.5 now so just adding that restriction there seems to make everything work out.

I'm deploying the CI images for 8.6.5 atm, as soon as that's done I'll push the new series to ci.

Our CI setup is a bit weird, unfortunately GitLab CI doesn't allow you to run CI for Github PRs yet, it's a planned feature though. Usually I just give people push access to the repo so they can just recreate the PR from a branch in the repo, which are built by CI.

If anyone has a better solution for a CI system that allows you to 1) use your own build server and 2) let's you run builds locally for testing I'd be happy to consider it. (GitLab CI allows this through the gitlab-runner exec command)

I used to maintain a thing that would allow doing that with travis: travis-run but I got tired of having to use their crappy pre-determined CI images.

[DanielG]

CI passes fine, yey. Here you are: https://hackage.haskell.org/package/cabal-helper-0.8.2.0