Merge #1215

1215: fix: use the correct type to determine ts target r=KnisterPeter a=KnisterPeter


<details>
<summary>Bors merge bot cheat sheet</summary>

We are using [bors-ng](https://github.com/bors-ng/bors-ng) to automate merging of our pull requests. The following table provides a summary of commands that are available to reviewers (members of this repository with push access) and delegates (in case of `bors delegate+` or `bors delegate=[list]`).

| Syntax | Description |
| --- | --- |
| bors merge | Run the test suite and push to master if it passes. Short for "reviewed: looks good." |
| bors merge- | Cancel an r+, r=, merge, or merge= |
| bors try | Run the test suite without pushing to master. |
| bors try- | Cancel a try |
| bors delegate+ | Allow the pull request author to merge their changes. |
| bors delegate=[list] | Allow the listed users to r+ this pull request's changes. |
| bors retry | Run the previous command a second time. |

This is a short collection of opinionated commands. For a full list of the commands read the [bors reference](https://bors.tech/documentation/).

</details>


Co-authored-by: Markus Wolf <[email protected]>

packages/typescript/mixin.core.js

@@ -81,7 +81,7 @@ class TypescriptMixin extends Mixin {
 
     const compilerOptions = getCompilerOptions(ts, rootDir);
     const properties = {
-      target: ts.ModuleKind.ESNext,
+      target: ts.ScriptTarget.ESNext,
       moduleResolution: ts.ModuleResolutionKind.NodeJs,
     };