Update known wrapper checksums (#810)

Automatically generated pull request to update the known wrapper
checksums.

In case of conflicts, manually run the workflow from the [Actions
tab](https://github.com/gradle/actions/actions/workflows/update-checksums-file.yml),
the changes will then be force-pushed onto this pull request branch.
Do not manually update the pull request branch; those changes might get
overwritten.

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Co-authored-by: bot-githubaction <bot-githubaction@gradle.com>
Co-authored-by: Jérôme Prinet <jprinet@gradle.com>

sources/src/wrapper-validation/wrapper-checksums.json

@@ -1,4 +1,12 @@
 [
+  {
+    "version": "9.4.0-milestone-4",
+    "checksum": "08f6dc44dc11cd44fdf485274f3262acd459acbcbc3c1160da2d530cecc9d1ad"
+  },
+  {
+    "version": "9.3.0-rc-2",
+    "checksum": "b3a875ddc1f044746e1b1a55f645584505f4a10438c1afea9f15e92a7c42ec13"
+  },
   {
     "version": "9.4.0-milestone-3",
     "checksum": "b3a875ddc1f044746e1b1a55f645584505f4a10438c1afea9f15e92a7c42ec13"