RFR: 8333685: Make update-copyright-year script more useful [v3]

[Sonia Zaldana Calles]

> Hi all, 
> 
> This PR addresses [8333685](https://bugs.openjdk.org/browse/JDK-8333685). 
> 
> I have added the following enhancements: 
> - Removed uses of `fgrep` and `egrep` with `grep -F` and `grep -E` respectively. 
> - Altered default behaviour to limit the processed changesets to those in the current branch and the current year. 
> - Enabled an option to modify all changesets in the year if desired (this was the previous default behaviour). 
> - Added named parameters and enabled `--help`.
> - Removed mercurial support. 
> - Fixed a bug where copyright headers that didn't have a comma following the initial year of creation were not getting picked up. For example, [here](https://github.com/openjdk/jdk/blob/512b2b4f141f9a202984150b0427372e1a409a50/src/hotspot/cpu/zero/copy_zero.hpp#L3). 
> - Fixed a bug where copyright headers missing the copyright symbol (c) were not getting picked up. Refer to the example above as well. 
> 
> Thanks, 
> Sonia

Sonia Zaldana Calles has updated the pull request incrementally with two additional commits since the last revision:

 - Support for copyright headers that don't add a comma after final copyright year
 - Changes based on feedback

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

Changes:
  - all: https://git.openjdk.org/jdk/pull/19605/files
  - new: https://git.openjdk.org/jdk/pull/19605/files/483c7fa9..754213b4

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=19605&range=02
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=19605&range=01-02

  Stats: 9 lines in 1 file changed: 3 ins; 0 del; 6 mod
  Patch: https://git.openjdk.org/jdk/pull/19605.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/19605/head:pull/19605

PR: https://git.openjdk.org/jdk/pull/19605