[devel at bb.net] Mergeable Buildbot pull requests

[dustin at buildbot.net]

Mergeable pull requests:

https://github.com/buildbot/buildbot/issues/5957 - lazylogfiles broken on 3.0.2
https://github.com/buildbot/buildbot/pull/5956 - Make GerritStatusPush also work with GitPoller source
https://github.com/buildbot/buildbot/issues/5948 - worker version is shown incorrectly in the UI 
https://github.com/buildbot/buildbot/pull/5947 - OpenstackLatentWorker: Try to cleanup existing worker(s) before starting new
https://github.com/buildbot/buildbot/issues/5946 - FileUpload umask issues
https://github.com/buildbot/buildbot/issues/5943 - MailNotifier fails to send email
https://github.com/buildbot/buildbot/issues/5933 - buildbot try fails for files containing non utf-8 characters
https://github.com/buildbot/buildbot/issues/5930 - [Feature] Build summary tooltip improvements
https://github.com/buildbot/buildbot/pull/5929 - WIP: Implement reporter for code issues in a PR
https://github.com/buildbot/buildbot/issues/5906 - Message queue doesn't provide correct message for step finished
https://github.com/buildbot/buildbot/issues/5903 - flawed HashiCorpVaultSecretProvider implementation
https://github.com/buildbot/buildbot/issues/5902 - sqlalchemy.exc.ResourceClosedError from Builder.getOldestRequestTime()
https://github.com/buildbot/buildbot/issues/5890 - GitPoller uses constant workdir by default leading to crash with other GitPoller instances when it is not overridden
https://github.com/buildbot/buildbot/issues/5878 - FileUpload fails with exception when file is not available
https://github.com/buildbot/buildbot/issues/5877 - FileDownload fails with exception when file not available
https://github.com/buildbot/buildbot/issues/5875 - Rewriting www frontend from AngularJS to React 
https://github.com/buildbot/buildbot/issues/5872 - Migrate to alembic for database migrations
https://github.com/buildbot/buildbot/pull/5857 - fix import of `buildbot.www.ldapuserinfo.py` failing if ldap3 is not available
https://github.com/buildbot/buildbot/issues/5852 - Triggered builds fail with exception when owners property is not set
https://github.com/buildbot/buildbot/issues/5844 - Windows Worker: When TASKKILL fails on 'TERM', does not retry on 'KILL'
https://github.com/buildbot/buildbot/issues/5833 - Feature suggestion: More actions for the workers
https://github.com/buildbot/buildbot/issues/5832 - Lost connections not detected in some cases
https://github.com/buildbot/buildbot/issues/5823 - Last Changes divided by changes sources
https://github.com/buildbot/buildbot/issues/5818 - Failed to update "pending"
https://github.com/buildbot/buildbot/issues/5794 - gitpoller: exceptions must be classes or instances deriving from BaseException, not type
https://github.com/buildbot/buildbot/issues/5790 - util.Secret is not working for util.LdapUserInfo in master.cfg
https://github.com/buildbot/buildbot/issues/5770 - LogObserver triggers StopIteration exceptions
https://github.com/buildbot/buildbot/issues/5761 - No blame mail on 'Nightly' builds
https://github.com/buildbot/buildbot/issues/5759 - buildbot try --get-builder-names not working when builderNames of Try_Userpass scheduler is an IRenderable
https://github.com/buildbot/buildbot/issues/5751 - Add column with changelog info for build lists