Update dependencies for the Dart Debug Extension

[elliette]

A couple of the dependencies were out of date, which caused the following error when running dart pub get. This PR updates them to match the versions in DWDS.

Resolving dependencies... (1.2s)
Because analyzer >=1.0.0 <1.1.0 depends on _fe_analyzer_shared ^16.0.0 and analyzer >=1.1.0 <1.2.0 depends on
  _fe_analyzer_shared ^17.0.0, analyzer >=1.0.0 <1.2.0 requires _fe_analyzer_shared ^16.0.0 or ^17.0.0.
And because analyzer >=1.2.0 <1.3.0 depends on _fe_analyzer_shared ^18.0.0, analyzer >=1.0.0 <1.3.0 requires
  _fe_analyzer_shared ^16.0.0 or ^17.0.0 or ^18.0.0.
Because analyzer >=1.4.0 <1.5.0 depends on _fe_analyzer_shared ^20.0.0 and analyzer >=1.3.0 <1.4.0 depends on
  _fe_analyzer_shared ^19.0.0, analyzer >=1.3.0 <1.5.0 requires _fe_analyzer_shared ^19.0.0 or ^20.0.0.
Thus, analyzer >=1.0.0 <1.5.0 requires _fe_analyzer_shared ^16.0.0 or ^17.0.0 or ^18.0.0 or ^19.0.0 or ^20.0.0.
Because analyzer ^1.6.0 depends on _fe_analyzer_shared ^22.0.0 and analyzer >=1.5.0 <1.6.0 depends on _fe_analyzer_shared
  ^21.0.0, analyzer ^1.5.0 requires _fe_analyzer_shared ^21.0.0 or ^22.0.0.
Thus, analyzer ^1.0.0 requires _fe_analyzer_shared ^16.0.0 or ^17.0.0 or ^18.0.0 or ^19.0.0 or ^20.0.0 or ^21.0.0 or
  ^22.0.0.
And because every version of dwds from path depends on _fe_analyzer_shared ^31.0.0, dwds from path is incompatible with
  analyzer ^1.0.0.
And because build_web_compilers >=2.16.4 <3.2.0 depends on analyzer ^1.0.0 and build_web_compilers >=0.4.1 <2.16.4
  depends on glob ^1.1.0, if dwds from path and build_web_compilers >=0.4.1 <3.2.0 then glob ^1.1.0.
And because build_runner >=1.11.2 depends on glob ^2.0.0 and build_runner >=0.10.1 <1.12.0 depends on web_socket_channel
  ^1.0.9, if dwds from path and build_web_compilers >=0.4.1 <3.2.0 and build_runner >=0.10.1 then web_socket_channel
  ^1.0.9.
And because extension depends on both web_socket_channel ^2.0.0 and build_web_compilers >=1.2.0 <3.0.0, dwds from path is
  incompatible with build_runner >=0.10.1.
So, because extension depends on both build_runner ^1.5.0 and dwds from path, version solving failed.

[annagrin]

LGTM!