[pgpool-committers: 9535] pgpool: Doc: add release notes.

[Chen Ningwei]

Doc: add release notes.

Branch
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V4_2_STABLE

Details
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https://git.postgresql.org/gitweb?p=pgpool2.git;a=commitdiff;h=86955ee184fbae7500c5e406ea51304c35a7a473

Modified Files
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doc.ja/src/sgml/release-4.0.sgml | 110 +++++++++++++++++++
doc.ja/src/sgml/release-4.1.sgml | 155 ++++++++++++++++++++++++++
doc.ja/src/sgml/release-4.2.sgml | 216 +++++++++++++++++++++++++++++++++++++
doc/src/sgml/release-4.0.sgml    | 117 ++++++++++++++++++++
doc/src/sgml/release-4.1.sgml    | 166 ++++++++++++++++++++++++++++
doc/src/sgml/release-4.2.sgml    | 227 +++++++++++++++++++++++++++++++++++++++
6 files changed, 991 insertions(+)