Changes

debian-trixie-build: add libgcrypt20-dev

Add libgcrypt20-dev as it is needed by open5gs's dependency
freeDiameter:

../../../../../build/src/open5gs/subprojects/freeDiameter/include/freeDiameter/meson.build:146:15: ERROR: C shared or static library 'gcrypt' not found

Without this installed, gerrit-verifications for osmo-dev fails.

Change-Id: Ifc0cc2e3900530cb75651125c0f769f8689748b2