[Backport to 3.2.x][Fixes #7362] GDAL upgrade to issue wtih postgres 12 and higher (#7363)

[afabiani]

• GDAL upgrade to issue wtih postgres 12 and higher ogr2ogr doesn't work with PostgreSQL 12beta OSGeo/gdal#1692

• add bullseye to source list to get GDAL 3.2.1 instead of compiling it.

(cherry picked from commit 5f45545)

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