Merge branch 'master' into ao-session-info

* master:
  A simple check to reject obviously wrong validation code binaries (#1989)
  fix approval keytypes doc (#1988)
  add max_pov_size to runtime config and PersistedValidationData (#1984)
  Bump env_logger from 0.8.1 to 0.8.2 (#1981)
  Bump pin-project from 1.0.1 to 1.0.2 (#1982)