[eas-cli] Add message about concurrency add-on

[brentvatne]

Why

Let people know that they can add more concurrencies easily

How

Make the message more clear

Test Plan

[github-actions]

CodeMention:

File Patterns	Mentions
**/*	@szdziedzic, @khamilowicz, @sjchmiela
packages/eas-cli/src/build/**	@szdziedzic, @khamilowicz, @sjchmiela

[github-actions]

Size Change: -2.24 kB (0%)

Total Size: 52.9 MB

Filename	Size	Change
./packages/eas-cli/dist/eas-linux-x64.tar.gz	52.9 MB	-2.24 kB (0%)

_{compressed-size-action}

[brentvatne]

/changelog-entry chore Let folks know about the new concurrency add-on

[keith-kurak]

Left an idea for a verbiage tweak, but looks good to me!

[github-actions]

✅ Thank you for adding the changelog entry!

[codecov]

Codecov Report

Attention: Patch coverage is 0% with 3 lines in your changes missing coverage. Please review.

Project coverage is 53.09%. Comparing base (a346af2) to head (48a4700).
Report is 1 commits behind head on main.

Files with missing lines	Patch %	Lines
packages/eas-cli/src/build/build.ts	0.00%	3 Missing ⚠️

Additional details and impacted files

@@           Coverage Diff            @@
##             main    #2611    +/-   ##
========================================
  Coverage   53.09%   53.09%            
========================================
  Files         563      563            
  Lines       21399    21399            
  Branches     4390     4162   -228     
========================================
  Hits        11360    11360            
- Misses       9201    10010   +809     
+ Partials      838       29   -809     

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