cargo: bump syn from 1.0.72 to 1.0.73

Bumps [syn](https://github.com/dtolnay/syn) from 1.0.72 to 1.0.73.
- [Release notes](https://github.com/dtolnay/syn/releases)
- [Commits](https://github.com/dtolnay/syn/compare/1.0.72...1.0.73)

---
updated-dependencies:
- dependency-name: syn
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <support@github.com>

Cargo.lock

@@ -3636,9 +3636,9 @@ dependencies = [
 
 [[package]]
 name = "syn"
-version = "1.0.72"
+version = "1.0.73"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "a1e8cdbefb79a9a5a65e0db8b47b723ee907b7c7f8496c76a1770b5c310bab82"
+checksum = "f71489ff30030d2ae598524f61326b902466f72a0fb1a8564c001cc63425bcc7"
 dependencies = [
  "proc-macro2",
  "quote",

deltachat_derive/Cargo.toml

@@ -9,5 +9,5 @@ license = "MPL-2.0"
 proc-macro = true
 
 [dependencies]
-syn = "1.0.72"
+syn = "1.0.73"
 quote = "1.0.2"