Update versions as to not have CI fail (while fixing "non-failing" CI) (#164)

* Make README links usable

* Update versions under test

Otherwise it silently fails with "Error: Requested Erlang/OTP version
(23.2) not found in version list (should you be using option
'version-type': 'strict'?)", which is not too important since this
happens when setup-beam.js is included (which happens in the test
environment only)

* Fix failing Gleam test

I think `gleam check` requires OTP (execution complains about missing
`escript`) where `gleam format` does not

.github/workflows/ubuntu.yml

@@ -179,10 +179,10 @@ jobs:
           cd test-projects/erlang_rebar3
           rebar3 ct
         if: ${{matrix.combo.rebar3-version}}
-      - name: Type check Gleam project (without installing Erlang/OTP)
+      - name: Format Gleam project (without installing Erlang/OTP)
         run: |
           cd test-projects/gleam_gleam
-          gleam check
+          gleam format
         if: ${{ matrix.combo.gleam-version && !matrix.combo.otp-version }}
       - name: Run Gleam project tests (without `rebar3`)
         run: |