Fix Selective Test Execution on PRs (#4205)

b26fb7c
removed one of the `chmod`s that was necessary to keep the filesystem
permissions consistent, this PR puts it back

Tested using this PR, verified that the touched
`example.cli.builtins[1-builtin-commands].local.test` test is the only
one picked up by test selection
(https://github.com/com-lihaoyi/mill/actions/runs/12545856782/job/34980872995?pr=4205),
the rest are all skipped

Author: lihaoyi

.github/actions/post-build-setup/action.yml

@@ -21,7 +21,7 @@ runs:
 
     # Need to fix cached artifact file permissions because github actions screws it up
     # https://github.com/actions/upload-artifact/issues/38
-    - run: "chmod -R +x ."
+    - run: "chmod -R 777 ."
       shell: bash
 
     - uses: coursier/cache-action@v6

example/cli/builtins/1-builtin-commands/build.mill

@@ -404,4 +404,4 @@ kotlinlib/web/1-hello-ktor
 // projects closest to what you want into the empty folder. Even though the example
 // project isn't going to be everything that you need, at least it'll get most of the
 // tedious boilerplate set up, so you can hit the group running working on the things
-// that are unique to your particular project.
+// that are unique to your particular project..