serde: Fix datetime human readable parsing

We are serializing as plain strings in this mode, so we also need to deserialize
with plain strings. The previous code tried to deserialize from a newtype struct
string.

Author: syyyr

Cargo.toml

@@ -5,7 +5,7 @@ name = "shvproto"
 description = "Rust implementation of the SHV protocol"
 license = "MIT"
 repository = "https://github.com/silicon-heaven/libshvproto-rs"
-version = "6.1.4"
+version = "6.1.5"
 edition = "2024"
 
 [dependencies]

src/serde/de.rs

@@ -431,7 +431,11 @@ impl<'de> serde::Deserialize<'de> for crate::DateTime {
             }
         }
 
-        deserializer.deserialize_newtype_struct("DateTime", DateTimeVisitor)
+        if deserializer.is_human_readable() {
+            deserializer.deserialize_str(DateTimeVisitor)
+        } else {
+            deserializer.deserialize_newtype_struct("DateTime", DateTimeVisitor)
+        }
     }
 }