Bump Iris, big rename of modalities.

opam

theories/escrows.v

theories/examples/circ_buffer.v

theories/examples/hashtable.v

theories/examples/kvnode.v

theories/examples/message_passing.v

theories/examples/msqueue.v

theories/examples/ro_test.v

theories/examples/ticket_lock.v

theories/examples/tstack.v

theories/gps/fractional.v

theories/gps/plain.v

theories/gps/singlewriter.v

theories/invariants.v

theories/logically_atomic.v