build: Update library version
Release 5.20
android/health: Fix queue creation for mdeps and devices

Create queue for mdeps, devices and channels when creating app
and device struct. It is simpler to read code than on demand
creation.
client: Wait for D-Bus before processing stdin

This should make it possible to do some scripting with bluetoothctl.
Otherwise stdin is processed before we're connected to D-Bus and most
commands will fail as a consequence.
doc: Add mode for enabling generation of debug keys
doc: Add management support for handling connection parameters
doc: Add extra mode for a reduced LE privacy mode
doc/mgmt-api: Fix a couple of typos
doc: Add comment for single mode controllers without public address
android/ipc-tester: Fix possible double close

I case of error we may close fd and pipe twice.
tools/mpris-player: Fix overflow before type widening

Expression is evaluated using 32-bit arithmetic before conversion to
64-bit.
queue: Fix unreachable code

I assume passing function == NULL means using direct_match() so make it
reachable.
tools/csr: Fix wrong error check
monitor: Fix checking boolean return value

Since btsnoop_read_hci() is used from src/shared.
bnep: Fix redundant check
hcitool: Fix adding missing break
hciconfig: Fix adding missing break
shared/att: Introduce struct bt_att.

This patch introduces struct bt_att, which handles the transport and
encoding/decoding for the ATT protocol. The structure of the code
follows that of src/shared/mgmt and lib/mgmt.h, where individual
parameter structures are defined for all ATT protocol requests, responses,
commands, indications, and notifications. The serialization and
endianness conversion for all parameters are handled by bt_att.

struct bt_att is based around struct io and operates on a raw file
descriptor.
shared/att: Implement basic boilerplate.

This patch implements the getters, setters, creation, ref, and unref
functions for struct bt_att. Also added is a simple table for
determining the ATT op type given an opcode and the io read handler that
currently does nothing.
shared/att: Implement write handler and bt_att_send.

This patch implements the write handler logic, including the way send
operations are process from the various internal queues. Added PDU
encoding for the Exchange MTU request.