change ULID to UUID v7 for immutable ledger design specs

Author: Mr-Leshiy

docs/src/architecture/08_concepts/immutable_ledger/cddl/block.cddl

@@ -8,20 +8,19 @@ block = [
 ]
 
 block-header = [
-    chain-id: ULID,
+    chain-id: UUID, ; UUID v7
     height: int,
     timestamp: #6.1(uint .ge 1722470400), ; Epoch-based date/time
     prev-block-id: hash-bytes, ; hash of the previous block
-    ?ledger-type: UUID,
-    ?purpose-id: ULID / UUID,
+    ?ledger-type: UUID, ; UUID v4
+    ?purpose-id: UUID, ; UUID v7
     ?validator,
     ~metadata,
 ]
 
 block-data = encoded-cbor
 
 UUID = #6.37(bytes) ; UUID type
-ULID = #6.32780(bytes) ; ULID type
 
 kid = hash-bytes ; hash of the x509/c509 certificate
 

docs/src/architecture/08_concepts/immutable_ledger/cddl/genesis_to_prev_hash.cddl

@@ -2,15 +2,14 @@
 ; https://datatracker.ietf.org/doc/html/draft-ietf-cbor-cde-06
 
 genesis-to-prev-hash = [
-    chain-id: ULID,
+    chain-id: UUID, ; UUID v7
     timestamp: #6.1(uint .ge 1722470400), ; Epoch-based date/time
-    ledger-type: UUID,
-    purpose-id: ULID / UUID,
+    ledger-type: UUID, ; UUID v4
+    purpose-id: UUID, ; UUID v7
     validator,
 ]
 
 UUID = #6.37(bytes) ; UUID type
-ULID = #6.32780(bytes) ; ULID type
 
 validator = (kid / [2* kid])
 kid = hash-bytes ; hash of the x509/c509 certificate