msggen: Switch signatures to string instead of bytes

Author: cdecker

cln-grpc/proto/node.proto

@@ -16,7 +16,7 @@
     'number': 'double',
     'pubkey': 'bytes',
     'short_channel_id': 'string',
-    'signature': 'bytes',
+    'signature': 'string',
     'string': 'string',
     'txid': 'bytes',
     'u8': 'uint32',  # Yep, this is the smallest integer type in grpc...

cln-rpc/src/model.rs

@@ -25,7 +25,7 @@
     'number': 'f64',
     'pubkey': 'PublicKey',
     'short_channel_id': 'ShortChannelId',
-    'signature': 'Vec<u8>',
+    'signature': 'String',
     'string': 'String',
     'txid': 'String',
     'float': 'f32',