feat(esbuild): add 'sourcemap' option to configure sourcemap generation

[mattsoulanille]

PR Checklist

Please check if your PR fulfills the following requirements:

• Tests for the changes have been added (for bug fixes / features)
• Docs have been added / updated (for bug fixes / features)

I'm pretty sure docs are auto-generated from the doc kwarg of attributes. If not, then docs have not been updated.

PR Type

What kind of change does this PR introduce?

• Bugfix
• Feature (please, look at the "Scope of the project" section in the README.md file)
• Code style update (formatting, local variables)
• Refactoring (no functional changes, no api changes)
• Build related changes
• CI related changes
• Documentation content changes
• Other... Please describe:

What is the current behavior?

Currently, there is no way to have esbuild include inlined sourcemaps in the output bundle.

Issue Number: N/A

What is the new behavior?

By passing sourcemap_inline = True to an esbuild rule named bundle, sourcemaps will be generated inline in bundle.js as well as externally in bundle.js.map.

Does this PR introduce a breaking change?

• Yes
• No

Other information

The motivation behind this feature is to make it easier to use esbuild as part of a development server. Inline sourcemaps are easier to correctly set up than external sourcemaps.

The argument is named sourcemap_inline instead of sourcemap since it can only add inline sourcemaps to the bundle. We can't let users directly change the sourcemap argument to esbuild, since that argument can turn off the generation of the external sourcemap file, which is a required output of the rule.

[mattsoulanille]

Actually, this doesn't solve the problem I was having with sourcemaps on my dev server, and it doesn't seem to be necessary. Setting sourcemap_content = True is what I needed.

I'm still going to open this PR in case this feature is useful, but feel free to close it.

[mattem]

lgtm thanks! 🙏