Switch Agda version to get bugfix
Switch Agda version to get bugfix

With this code, we include the Agda version with the first fix for
agda/agda#1985 (agda/agda@a06c2095c7668a34406c4c7f4c8f4be1ee17af86).

Part of the issue is still there, but now working around it seems more
plausible.

inc-lc/ilc-agda