pgsql: ci: Increase requested memory size.

ci: Increase requested memory size.

CI builds recently started failing with:

"Memory size for 4.0 vCPU instance should be between 3840MiB and
26624MiB, while 2048MiB is requested."

Ok then, let's ask for 4G instead of 2G.

This may be due to a change in the type of instance used to work around
an outage, per:

https://twitter.com/cirrus_labs/status/1572657320093712384

Branch
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REL_15_STABLE

Details
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https://git.postgresql.org/pg/commitdiff/08ddb3c0852d87394b44eea45709b9d9b8154f68

Modified Files
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.cirrus.yml | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)