Rewrite the README file

Inspired by brian d foy's style[1].

Ref: [1] https://metacpan.org/source/BDFOY/Set-CrossProduct-1.96/README
CheckJira: implement option githooks.checkjira.status

By default, it doesn't matter in which status the JIRA issues are. By
setting this multi-valued option one can restrict the valid statuses for
the issues.
CheckJira: implement option githooks.checkjira.issuetype

By default, it doesn't matter what type of JIRA issues are cited. By
setting this multi-valued option one can restrict the valid issue types.
CheckJira: implement option githooks.checkjira.fixversion

This multi-valued option allows one to specify that commits affecting a
specific BRANCH must cite only JIRA issues that have their 'Fix For
Version' field matching specific VERSIONS. This may be useful if one has
release branches associated with particular JIRA versions.
v1.2.0

  [New features]

  - CheckJira: implement option githooks.checkjira.status.

  - CheckJira: implement option githooks.checkjira.issuetype.

  - CheckJira: implement option githooks.checkjira.fixversion.