Bump Scala 3 to RC1

[anatoliykmetyuk]

This currently fails due to a reworked API of TASTy Reflect:

[error] -- [E006] Not Found Error: /Users/kmetiuk/Projects/scala3/tools/dotty-release-scripts/ecosystem_projects/foo/inspector/src/main/scala/inspector/Inspector.scala:11:24
[error] 11 |    val inspector = new TastyInspector {
[error]    |                        ^^^^^^^^^^^^^^
[error]    |                        Not found: type TastyInspector
[error] -- [E008] Not Found Error: /Users/kmetiuk/Projects/scala3/tools/dotty-release-scripts/ecosystem_projects/foo/inspector/src/main/scala/inspector/Inspector.scala:18:14
[error] 18 |    inspector.inspectTastyFiles(List(tastyFile))
[error]    |    ^^^^^^^^^^^^^^^^^^^^^^^^^^^
[error]    |    value inspectTastyFiles is not a member of Object

inspector project relies on the processCompilationUnit method which was removed. Using TastyInspector object directly without that method results in tests failures (read null instead of some meaningful content). @nicolasstucki any idea how to fix this?

[nicolasstucki]

The API changed. I will update it.

[nicolasstucki]

@anatoliykmetyuk branches should be created in dotty-staging, not in this repo just as we do for dotty.

[nicolasstucki]

Replaced with #12