CI fixes for #1598, #1599

[RyanGlScott]

Two CI fixes:

Switch from haskell/actions/setup to haskell-actions/setup

Fixes #1598.

Pin alex to 3.4.0.1 in cryptol-remote-api Dockerfile

Fixes #1599.

[kquick]

Just a couple of suggestions for additional documentation.

[RyanGlScott]

Sigh. I should have kicked off a separate, nightly pipeline to test my last commit, since it ended up being subtly incorrect. See this CI error:

 > [toolchain 6/6] RUN if true; then         ghcup install ghc 8.10.2 &&         ghcup set ghc 8.10.2 &&         cabal v2-update &&         cabal v2-install alex-${ALEXVER} happy-${HAPPYVER} &&         git clone --recurse-submodules --depth 1 --branch ghc-9.2.8-release https://gitlab.haskell.org/ghc/ghc.git &&         cd ./ghc &&         git apply ../ghc-portability.patch &&         ./boot &&         ./configure &&         make -j &&         make install &&         cd .. &&         rm -rf ./ghc &&         ghcup rm ghc 8.10.2;     else         ghcup install ghc 9.2.8 &&         ghcup set ghc 9.2.8;     fi:
49.64 Config file path source is default config file.
49.64 Config file not found: /root/.config/cabal/config
49.64 Writing default configuration to /root/.config/cabal/config
49.79 Downloading the latest package list from hackage.haskell.org
66.74 Package list of hackage.haskell.org has been updated.
66.74 The index-state is set to 2024-01-05T06:50:50Z.
66.78 Error: cabal: Invalid package ID: alex-
66.78 "<eitherParsec>" (line 1, column 6):
66.78 unexpected end of input

Judging from that error message, ALEXVER didn't get substituted into alex-${ALEXVER} because I failed to put ARG ALEXVER in the stage of the Dockerfile that references ALEXVER. I'll submit a follow-up patch shortly (and properly test it this time).

[kquick]

No good deed... Been there, done that. C'est la vie, and all that bolderdash. :-)