Bump rules_cc to 2f8c04c

[shaldengeki]

This is my first contribution to rules_proto -- greatly appreciate your patience! I've already signed the CLA on my own behalf.

Fixes #95.

This bumps rules_cc to (as of writing) HEAD, authored ~21 days ago:
bazelbuild/rules_cc@2f8c04c

To verify, I:

• reproduced the error described in Conflict with rules proto: "cannot load '@rules_cc//cc:action_names.bzl': no such file" erenon/bazel_clang_tidy#8
• Updated bazel_clang_tidy's version of rules_proto to this commit, and verified that the error no longer occurred:

ouguoc:~/bazel_clang_tidy$ bazel build //example:app     --aspects clang_tidy/clang_tidy.bzl%clang_tidy_aspect     --output_groups=report
INFO: Analyzed target //example:app (0 packages loaded, 0 targets configured).
INFO: Found 1 target...
INFO: From Run clang-tidy on example/app.cpp:
3005 warnings generated.
Suppressed 3005 warnings (3005 in non-user code).
Use -header-filter=.* to display errors from all non-system headers. Use -system-headers to display errors from system headers as well.
Aspect //clang_tidy:clang_tidy.bzl%clang_tidy_aspect of //example:app up-to-date:
  bazel-bin/example/example/app.cpp.app.clang-tidy.yaml
INFO: Elapsed time: 2.845s, Critical Path: 2.65s
INFO: 2 processes: 1 internal, 1 local.
INFO: Build completed successfully, 2 total actions