west.yml: Update zcbor to v. 0.5.1

lwm2m: Regenerate lwm2m_senml code from the CDDL description.
Reapply manual changes.
Create a sh script to perform the regeneration.

tests: zcbor_bulk: Adapt to zcbor 0.5.1
zcbor_new_decode_state() now has no return value.

Signed-off-by: Øyvind Rønningstad <oyvind.ronningstad@nordicsemi.no>

subsys/net/lib/lwm2m/lwm2m_senml_cbor.cddl

@@ -0,0 +1,25 @@
+lwm2m_senml = [1* record]
+
+record = {
+	? bn => tstr,            ; Base Name
+	? n => tstr,             ; Name
+	? ( vi => int .size 8 // ; Integer Value
+	    vf => float       // ; Float Value
+	    vs => tstr        // ; String Value
+	    vb => bool        // ; Boolean Value
+	    vd => bstr ),        ; Data Value
+	0*3 key-value-pair       ; To handle unordered maps; length-first ordered map keys
+}
+
+; now define the generic versions
+key-value-pair = ( int => value )
+
+value = tstr / bstr / int .size 8 / float / bool
+
+n  = 0
+bn = -2
+vi = 2
+vf = 2
+vs = 3
+vd = 8
+vb = 4