Reintroduce support for Webpack 4 in Vue Apollo Composable

[HansCronau]

Description
@vue/apollo-composable 4.0.0-alpha.13 broke support for webpack 4 by using a nullish coalescing operator.
As discussed in issue #1217, webpack 4 uses acorn 6, while support for the nullish coalescing operator was only added in acorn 7.
Users of webpack 4 will now get the error: Module parse failed: Unexpected token (19:103).
Reintroducing support for webpack 4 would be especially useful for users who have abstracted away webpack.

Proposed solution
On issue #1217, @Akryum commented that he would probably lower the esbuild target to what acorn 6 understands.

Alternatives
Alternatives are upgrading to webpack 5 or freezing @vue/apollo-composable at 4.0.0-alpha.12.
I see that @tobiasdiez from issue #1217 has resorted to transpiling @vue/apollo-composable with babel.

Updating to webpack 5 is hard for those who use @vue/cli-service to abstract away webpack. Manually transpiling @vue/apollo-composable is also not ideal.
Since I believe the intention is to reintroduce support for webpack 4 within @vue/apollo-composable, I'm currently holding at 4.0.0-alpha.12.

[Akryum]

Per the webpack team, transpiling dependencies is not a bad idea. Instead of going with the lower common denominator (IE) leading to shipping older and heavier code, it would probably better that the ecosystem goes towards the opposite = let the final 'user' decide what to transpile to which target - especially when the code being transpiled is fully valid standard JS.

[HansCronau]

@Akryum, I completely agree. But am I correct in observing that in this case the lowest common denominator is acorn 6, used by webpack 4, installed by the Vue CLI for projects in Vue 2, which is still the current version of Vue?
Rather than using old and heavy code, I was under the impression that I was on the bleeding edge by using @vue/apollo-composable in my Vue 2 project. 😐

[Akryum]

Yes, that's why I said I'll change the target accordingly.

[HansCronau]

Cool. I probably mistakenly interpreted your comment as considering not going back.
Thanks for your work and quick responses!