build(deps-dev): update rake-compiler requirement from 1.2.7 to 1.2.8

Updates the requirements on [rake-compiler](https://github.com/luislavena/rake-compiler) to permit the latest version.
- [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:development
...

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

Author: dependabot[bot]

Gemfile

@@ -10,7 +10,7 @@ group :development do
   gem "rake", "13.2.1"
 
   # building extensions
-  gem "rake-compiler", "1.2.7"
+  gem "rake-compiler", "1.2.8"
   gem "rake-compiler-dock", "1.5.2"
 
   # parser generator