[pgpool-committers: 8971] pgpool: Doc: add release note.

[Bo Peng]

Doc: add release note.

Branch
------
V4_2_STABLE

Details
-------
https://git.postgresql.org/gitweb?p=pgpool2.git;a=commitdiff;h=c81d6cc8cbf83281261b0883e7e7dfe1b855c8d8

Modified Files
--------------
doc.ja/src/sgml/release-3.7.sgml | 117 ++++++++++++++++++++
doc.ja/src/sgml/release-4.0.sgml | 212 +++++++++++++++++++++++++++++++++++
doc.ja/src/sgml/release-4.1.sgml | 212 +++++++++++++++++++++++++++++++++++
doc.ja/src/sgml/release-4.2.sgml | 221 +++++++++++++++++++++++++++++++++++++
doc/src/sgml/release-3.7.sgml    | 123 +++++++++++++++++++++
doc/src/sgml/release-4.0.sgml    | 224 +++++++++++++++++++++++++++++++++++++
doc/src/sgml/release-4.1.sgml    | 224 +++++++++++++++++++++++++++++++++++++
doc/src/sgml/release-4.2.sgml    | 233 +++++++++++++++++++++++++++++++++++++++
8 files changed, 1566 insertions(+)