updated README docs for PubSub Events

updated README to include DebugLog middleware entry

update to v0.5.1 for tagging issue

update version to 0.5.0

updated changelog to include PR link

Expanded error handling, DebugLog middleware, and pause/resume support (#50)

updated changelog

Merge pull request #49 from sagents-ai/me-dep-bump

update to langchain 0.7.0

Merge pull request #48 from sagents-ai/me-more-docs-updates

make the doc module references fully qualified

Merge pull request #47 from sagents-ai/me-fix-docs

fix documentation

Merge pull request #46 from sagents-ai/me-prep-for-release

prep for v0.4.3 release