pgsql: ci: enable zstd where available.

ci: enable zstd where available.

Since zstd is now used in a bunch of places, enable it in CI. The windows
image unfortunately doesn't yet contain zstd, so it's not enabled there.

Discussion: https://postgr.es/m/20220330155017.lfnlzt3m42nk7kff@alap3.anarazel.de

Branch
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master

Details
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https://git.postgresql.org/pg/commitdiff/ff50baec65bba1a839322ba8bcb3efcd08f40621

Modified Files
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.cirrus.yml | 8 ++++++--
1 file changed, 6 insertions(+), 2 deletions(-)