Merge pull request scala#5381 from SethTisue/use-rc1-as-starr

bump STARR to 2.12.0-RC1

Author: adriaanm

versions.properties

@@ -8,7 +8,7 @@
 # The scala version used for bootstrapping. This has no impact on the final classfiles:
 # there are two stages (locker and quick), so compiler and library are always built
 # with themselves. Stability is ensured by building a third stage (strap).
-starr.version=2.12.0-M5
+starr.version=2.12.0-RC1
 
 # These are the versions of the modules that go with this release.
 # These properties are used during PR validation and in dbuild builds.
@@ -19,7 +19,7 @@ starr.version=2.12.0-M5
 #  - After 2.x.0 is released, the binary version is 2.x.
 #  - During milestones and RCs, modules are cross-built against the full version.
 #    So the value is the full version (e.g. 2.12.0-M2).
-scala.binary.version=2.12.0-M5
+scala.binary.version=2.12.0-RC1
 
 # external modules shipped with distribution, as specified by scala-library-all's pom
 scala-xml.version.number=1.0.5