build: bump syn from 1.0.76 to 1.0.77 in /fuzz

Bumps [syn](https://github.com/dtolnay/syn) from 1.0.76 to 1.0.77.
- [Release notes](https://github.com/dtolnay/syn/releases)
- [Commits](https://github.com/dtolnay/syn/compare/1.0.76...1.0.77)

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

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

fuzz/Cargo.lock

@@ -354,9 +354,9 @@ dependencies = [
 
 [[package]]
 name = "linux-loader"
-version = "0.3.0"
+version = "0.4.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "c819cc8275b0f2c1ed9feec455ca288b45d82932384a6a5f7a86812ee3427459"
+checksum = "8a5e77493808403a6bd56a301a64ea6b9342e36ea845044bf0dfdf56fe52fa08"
 dependencies = [
  "vm-memory",
 ]
@@ -585,9 +585,9 @@ checksum = "8ea5119cdb4c55b55d432abb513a0429384878c15dde60cc77b1c99de1a95a6a"
 
 [[package]]
 name = "syn"
-version = "1.0.76"
+version = "1.0.77"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "c6f107db402c2c2055242dbf4d2af0e69197202e9faacbef9571bbe47f5a1b84"
+checksum = "5239bc68e0fef57495900cfea4e8dc75596d9a319d7e16b1e0a440d24e6fe0a0"
 dependencies = [
  "proc-macro2",
  "quote",
@@ -887,6 +887,7 @@ dependencies = [
  "versionize",
  "versionize_derive",
  "vfio-ioctls",
+ "vfio_user",
  "vhdx",
  "virtio-devices",
  "vm-allocator",