Fixup action name for the GH marketplace

[starbelly]

We seemed to have published to the marketplace previously with a description of the action vs the action name. This commit changes the name to simply setup-beam.

The link that is out there : https://github.com/marketplace/actions/setup-erlang-otp-with-optional-elixir-and-mix-and-or-rebar3

Additionally, if you search for setup-beam or beam this will action not come up. We may want to revise the description while we are here.

• [x] I have performed a self-review of my changes
• [x] I have read and understood the contributing guidelines

[paulo-ferraz-oliveira]

I did the first change to the name, and at that time I didn't look at the action.yml reference. The description was previously "Setup Elixir" 😄, here.

[paulo-ferraz-oliveira]

Something like

  This action's goal is to set up a BEAM-based CI environment, with
  Erlang/OTP as a base, then optionally, Elixir, Gleam, `rebar3` or `hex`
  on top of that

?

I'm also Ok merging this now and changing the description in a subsequent pull request.

[paulo-ferraz-oliveira]

Bryan, I'm merging this to check if the verification process moves forward, and then I'll pr to fix the description 😄 I'm eager to see if this unblocks the verification process 😄