[bazel] Fix CI on MacOS (#583)

- Adds platform specific build flag --macos_minimum_os=10.15 to target recent Apple C++ SDK versions only, which support the std::filesystem API. I added the flag to .bazelrc and removed the unused .github/workflows/ci.bazelrc file.
- Also enabled test_output=errors in bazel CI to provide better error messages for failed test cases.

Signed-off-by: Shameek Ganguly <shameek@intrinsic.ai>

Author: shameekganguly

.bazelrc

@@ -13,3 +13,7 @@ build --features=per_object_debug_info
 
 # Enable header processing, required for layering checks with parse_header.
 build --process_headers_in_dependencies
+
+# OS specific settings
+build --enable_platform_specific_config
+build:macos --macos_minimum_os=10.15

.github/workflows/bazel.yml

@@ -23,3 +23,4 @@ jobs:
           {"folder": ".", "bzlmodEnabled": false},
         ]
       exclude_windows: true
+      bazel_test_command: "bazel test --test_output=errors //..."