Update release procedure in contributing.md (#4339)

1. Remove schemas updates - it's now in semantic-conventions
2. Remove manual step to update opentelemetry.io - it's automated
3. Add manual check for broken link anchors (see
open-telemetry/semantic-conventions#1009,
#4338 for the context)

CONTRIBUTING.md

@@ -289,34 +289,15 @@ Release Procedure:
 
 1. Prepare a [draft release here](https://github.com/open-telemetry/opentelemetry-specification/releases).
    Don't publish it yet.
-2. Create a PR with updated [CHANGELOG.md](CHANGELOG.md). The CHANGELOG.md must have a
+2. Run [opentelemetry.io workflow](https://github.com/open-telemetry/opentelemetry.io/actions/workflows/build-dev.yml)
+   against `opentelemetry-specification` submodule as a smoke-test for docs. Fix broken links, if any.
+3. Create a PR with updated [CHANGELOG.md](CHANGELOG.md). The CHANGELOG.md must have a
    heading with the new version number. Ensure that no CHANGELOG entries are missing or
    ended up in the wrong section (e.g., in the last released version rather than Unreleased).
-   The PR will fail the `schemas-check` Github action (all other actions must pass).
-   This is expected and will be fixed in the next steps. Have this PR reviewed and approved
-   and ready to be merged. While it is being reviewed you can work on step 3-4 in parallel.
-3. Prepare the schema file for the upcoming release. The schema file should be placed
-   in the `schemas` directory. If no changes to semantic conventions happened
-   since the last release which require a corresponding section in the schema file then
-   simply copy the previous schema file, rename it to the new version and add a section
-   with the new version number to the file. See for example the schema file for [1.9.0](
-   https://github.com/open-telemetry/opentelemetry-specification/blob/main/schemas/1.9.0)
-   that has no changes from 1.8.0.
-   The schema file may already exist if there were changes done to semantic conventions
-   and the schema file was created with corresponding changes.
-4. Create and merge the PR with the new schema file. Note the commit hash after merging.
-   If the schema file for the new release version previously existed then no new PR is
-   necessary, just note that latest commit hash of this repository.
-5. Once CHANGELOG.md PR is approved and ready to be merged we are ready to make the release.
-   Update the [opentelemetry.io](https://github.com/open-telemetry/opentelemetry.io)
-   repository: the [opentelemetry-specification](
-   https://github.com/open-telemetry/opentelemetry.io/tree/main/content-modules)
-   submodule points to this repository. Create a PR and update the submodule to point to
-   the commit hash from step 4. Merge this PR. This should update the
-   [https://opentelemetry.io/](https://opentelemetry.io/) website and the new schema file
-   should be downloadable at `https://opentelemetry.io/schemas/<version>`.
-6. Re-trigger the `schema-checks` Github action on the PR that updates the CHANGELOG.md.
-   The action should pass now. Merge the PR.
-7. Add the changelog entries from `CHANGELOG.md` to the description of the previously
+4. Once CHANGELOG.md PR is approved and ready to be merged we are ready to make the release.
+5. Add the changelog entries from `CHANGELOG.md` to the description of the previously
    created [draft release here](
    https://github.com/open-telemetry/opentelemetry-specification/releases) and publish it.
+
+New release is then auto-discovered by [opentelemetry.io](https://github.com/open-telemetry/opentelemetry.io) pipelines which
+(via bot-generated PR) will eventually publish new version of the specification.