RFR: 1385: Backport MR links to the wrong CSR request [v5]

[Guoxiong Li]

> Hi all,
> 
> This patch solves the wrong CSR in the backport PR. It mainly has the following rules:
> 1. if the `version` in `.jcheck/conf` doesn't exist or the `version` is wrong, the bot think the CSR also doesn't exist.
> 2. else, if the `version` in `.jcheck/conf` matches the fix version of the primary CSR, the bot will use the primary CSR. (primary CSR is the CSR of the primary issue)
> 3. else, if these is a backport issue matches the `version`, the bot will find the CSR of the backport issue. If found, use it. If not, the bot think the CSR doesn't exist.
> 4. else (no backport issue matches the `version`) the bot think the CSR doesn't exist.
> 
> The classes `CSRBot`, `CheckRun` and `CSRCommand` will handle the situations above respectively.
> 
> Thanks for taking the time to review.
> 
> Best Regards,
> -- Guoxiong

Guoxiong Li has updated the pull request incrementally with one additional commit since the last revision:

  Move the methods from IssueUtil to Backports.

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

Changes:
  - all: https://git.openjdk.java.net/skara/pull/1318/files
  - new: https://git.openjdk.java.net/skara/pull/1318/files/d340a6cf..8aa52dc5

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=skara&pr=1318&range=04
 - incr: https://webrevs.openjdk.java.net/?repo=skara&pr=1318&range=03-04

  Stats: 324 lines in 7 files changed: 123 ins; 194 del; 7 mod
  Patch: https://git.openjdk.java.net/skara/pull/1318.diff
  Fetch: git fetch https://git.openjdk.java.net/skara pull/1318/head:pull/1318

PR: https://git.openjdk.java.net/skara/pull/1318