2 additional ways to trigger your builds in Pipelines

This post introduces two new ways to trigger Bitbucket Pipelines: manual triggers and tag-based triggers. Manual triggers are configured via a `custom` pipeline in `bitbucket-pipelines.yml` and can be invoked from the Bitbucket UI. Tag triggers are configured via a `tag` section in `bitbucket-pipelines.yml`, allowing pipelines to run when Git tags matching a specified pattern are pushed. The `BITBUCKET_TAG` environment variable is made available for tag-triggered builds.