RFR: Add support for marking PR body content with an expiration time [v2]

[Robin Westberg]

> For information in the PR body that is calculated using data from external sources (like Jira, another personal fork,
> etc.) we need to perform a periodical refresh, as our normal way of detecting updates cannot be used (the updatedAt
> field of a pull request).

Robin Westberg has updated the pull request incrementally with one additional commit since the last revision:

  Update bots/pr/src/main/java/org/openjdk/skara/bots/pr/CheckWorkItem.java
  
  Co-authored-by: Erik Duveblad <erik.helin at oracle.com>

-------------

Changes:
  - all: https://git.openjdk.java.net/skara/pull/862/files
  - new: https://git.openjdk.java.net/skara/pull/862/files/cd19ac11..1d6b7d42

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=skara&pr=862&range=01
 - incr: https://webrevs.openjdk.java.net/?repo=skara&pr=862&range=00-01

  Stats: 1 line in 1 file changed: 0 ins; 0 del; 1 mod
  Patch: https://git.openjdk.java.net/skara/pull/862.diff
  Fetch: git fetch https://git.openjdk.java.net/skara pull/862/head:pull/862

PR: https://git.openjdk.java.net/skara/pull/862