@opentelemetry/api@1.2.0 support

[trentm]

There is a dependabot PR to update to @otel/api@1.2.0: #2930
However, that is only part of the story. Here are some notes to complete that update.

• update our dep
• update the dep in examples/opentelemetry-bridge
• add dependabot on examples/opentelemetry-bridge/package.json
• 1.2.0 added getActiveSpan() to the trace API (see https://github.com/open-telemetry/opentelemetry-js-api/releases/tag/v1.2.0). IIUC this is implemented "API-side" (Special case API for getting the current span open-telemetry/opentelemetry-js-api#162 (comment)) so might not require any added support in the OTel Bridge. However, we should add it to our tests at the least.
• Add otel/api section or entry to supported-technologies and/or to the OTel Bridge doc.
• add a maint section to DEVELOPER.md or elsewhere on how to update for new OTel API versions, in general.

[trentm]

This was effectively done as part of #3152