chore(cargo): introduce syn 3 dependency

It is now used by at the latest versions of anyhow and thiserror,
so we will eventually have this duplicate dependency anyway.

Cargo.lock

@@ -1497,7 +1497,7 @@ name = "deltachat_derive"
 version = "2.0.0"
 dependencies = [
  "quote",
- "syn 2.0.118",
+ "syn 3.0.3",
 ]
 
 [[package]]
@@ -6061,6 +6061,17 @@ dependencies = [
  "unicode-ident",
 ]
 
+[[package]]
+name = "syn"
+version = "3.0.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "53e9bae58849f64dfa4f5d5ae372c8341f7305f82a3868709269343628b659a3"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "unicode-ident",
+]
+
 [[package]]
 name = "sync_wrapper"
 version = "1.0.0"

deltachat_derive/Cargo.toml

@@ -8,5 +8,5 @@ license = "MPL-2.0"
 proc-macro = true
 
 [dependencies]
-syn = "2"
+syn = "3"
 quote = "1"

deny.toml

@@ -90,6 +90,7 @@ skip = [
      { name = "strum_macros", version = "0.26.2" },
      { name = "strum", version = "0.26.2" },
      { name = "syn", version = "1.0.109" },
+     { name = "syn", version = "2.0.118" },
      { name = "thiserror-impl", version = "1.0.69" },
      { name = "thiserror", version = "1.0.69" },
      { name = "toml_datetime", version = "0.6.11" },