update h2 (#2982)

Fixes https://rustsec.org/advisories/RUSTSEC-2023-0034

Author: Geal

.changesets/fix_geal_update_h2.md

@@ -0,0 +1,5 @@
+### Update the h2 dependency to fix a Denial of Service vulnerability 
+
+Fixes https://rustsec.org/advisories/RUSTSEC-2023-0034
+
+By [@Geal](https://github.com/Geal) in https://github.com/apollographql/router/pull/2982

Cargo.lock

@@ -2528,9 +2528,9 @@ dependencies = [
 
 [[package]]
 name = "h2"
-version = "0.3.16"
+version = "0.3.18"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "5be7b54589b581f624f566bf5d8eb2bab1db736c51528720b6bd36b96b55924d"
+checksum = "17f8a914c2987b688368b5138aa05321db91f4090cf26118185672ad588bce21"
 dependencies = [
  "bytes",
  "fnv",