Bump rake-compiler from 1.2.7 to 1.2.8 in /gemfiles/3.0

Bumps [rake-compiler](https://github.com/luislavena/rake-compiler) from 1.2.7 to 1.2.8.
- [Release notes](https://github.com/luislavena/rake-compiler/releases)
- [Changelog](https://github.com/rake-compiler/rake-compiler/blob/master/History.md)
- [Commits](rake-compiler/rake-compiler@v1.2.7...v1.2.8)

---
updated-dependencies:
- dependency-name: rake-compiler
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <support@github.com>

gemfiles/3.0/Gemfile.lock

@@ -20,7 +20,7 @@ GEM
     power_assert (2.0.3)
     racc (1.8.1)
     rake (13.2.1)
-    rake-compiler (1.2.7)
+    rake-compiler (1.2.8)
       rake
     rbs (3.6.0)
       logger