bazel: fix bazel-registry checksum mismatch, create staged test_gcc and update Envoy dependency instructions

.bazelrc

@@ -40,8 +40,6 @@ startup --host_jvm_args="-DBAZEL_TRACK_SOURCE_DIRECTORIES=1"
 common --remote_executor=
 build --remote_executor=
 build --modify_execution_info=.*=+no-remote-exec
-common --registry=https://bcr.bazel.build/
-common --registry=https://raw.githubusercontent.com/envoyproxy/bazel-registry/main
 common --copt=-Iinclude
 common --cxxopt=-Iinclude
 # quiche
@@ -177,6 +175,7 @@ build --@quiche//:quiche_export_impl_lib=@envoy//source/common/quic/platform:qui
 build --@quiche//:quiche_flags_impl_lib=@envoy//source/common/quic/platform:quiche_flags_impl_lib
 build --@quiche//:quiche_logging_impl_lib=@envoy//source/common/quic/platform:quiche_logging_impl_lib
 build --@quiche//:quiche_lower_case_string_impl_lib=@envoy//source/common/quic/platform:quiche_lower_case_string_impl_lib
+build --@quiche//:quiche_mem_slice_impl_lib=@envoy//source/common/quic/platform:quiche_mem_slice_impl_lib
 build --@quiche//:quiche_platform_iovec_impl_lib=@envoy//source/common/quic/platform:quiche_platform_iovec_impl_lib
 build --@quiche//:quiche_stack_trace_impl_lib=@envoy//source/common/quic/platform:quiche_stack_trace_impl_lib
 build --@quiche//:quiche_time_utils_impl_lib=@envoy//source/common/quic/platform:quiche_time_utils_impl_lib

MAINTAINERS.md

@@ -37,7 +37,7 @@ with the latest revision weekly. Nighthawk reuses large parts of Envoy's build
 system and codebase, so keeping Nighthawk up to date with Envoy's changes is an
 important maintenance task.
 
-The update process can be completed by manually executing the steps documented on this [page]( https://github.com/envoyproxy/nighthawk/blob/69321419308f36078037a05a6b12b9819368d413/docs/root/updating_envoy_dependency.md) **or** running a utility script. The rest of this page provides instructions for using the utility script.
+The update process can be completed by manually executing the steps documented on this [page]( https://github.com/envoyproxy/nighthawk/blob/main/docs/root/updating_envoy_dependency.md) **or** running a utility script. The rest of this page provides instructions for using the utility script.
 
 ### Run the utility script