allow Win32-2.13

[robx]

Hackage has Win32-2.13.2.1 with what appear to be changes unrelated to how it's used in postgresql-libpq.

(I ran into this in a CI build with current stackage nightly, failing with

Error: While constructing the build plan, the following exceptions were encountered:
In the dependencies for postgresql-libpq-0.9.4.3:
Win32-2.12.0.1 from stack configuration does not match >=2.2.0.2 && <2.11  (latest matching
                   version is 2.10.1.1)
needed due to postgrest-9.0.1.20220630 -> postgresql-libpq-0.9.4.3

A build with allow-newer is in process here, which compiled postgresql-libpq successfully with Win32-2.12.0.1.)

[phadej]

Done in #29