Add nightly dependency bump workflow

[ezhang6811]

Issue #, if available:

Description of changes:
Add a workflow nightly-build.yml with following actions:

• creates or checks out existing nightly-dependency-updates branch
• checks for newest versions of dependencies in opentelemetry-js (core packages, experimental packages, api, and semconv) and opentelemetry-js-contrib (independently versioned packages), bumps versions if applicable, and creates/updates PR
• search for releases with breaking changes in release notes, and links in the PR
• runs main build checks on the branch, publishes a failure metric based on the outcome.

Example nightly build PR: #273

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