project/shaderc: remove Shaderc non-maintainers (#15212)

Don't cc folks who have never contributed to Shaderc.

Author: dneto0

projects/shaderc/project.yaml

@@ -1,12 +1,10 @@
 homepage: "https://github.com/google/shaderc"
 main_repo: "https://github.com/google/shaderc.git"
-primary_contact: "david@adalogics.com"
+primary_contact: "dneto@google.com"
 language: c++
 sanitizers:
 - address
 auto_ccs:
-- "adam@adalogics.com"
-- "arthur.chan@adalogics.com"
 - "dneto@google.com"
 - "dsinclair@google.com"
 - "fuzzing@fuchsia.dev"