build: remove es.js & replace it by .mjs

[Stun3R]

Types of changes

• Bug fix (a non-breaking change which fixes an issue)
• New feature (a non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)

Description

It seems that for some people the es.js extension doesn't work & the package is not recognised as an ES module

[netlify]

✔️ Deploy Preview for strapi-sdk-js canceled.

🔨 Explore the source changes: 16106d8

🔍 Inspect the deploy log: https://app.netlify.com/sites/strapi-sdk-js/deploys/61e5c0addac67d0008acb0c2

[codecov]

Codecov Report

Merging #119 (16106d8) into main (0c6ed77) will not change coverage.
The diff coverage is n/a.

@@            Coverage Diff            @@
##              main      #119   +/-   ##
=========================================
  Coverage   100.00%   100.00%           
=========================================
  Files            3         3           
  Lines          106       106           
  Branches        18        18           
=========================================
  Hits           106       106           

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update 0c6ed77...16106d8. Read the comment docs.