fix: address RUSTSEC-2026-0104 cargo-deny advisory (#3326)

## Summary

- Update `rustls-webpki` 0.103.10 → 0.103.13 to fix RUSTSEC-2026-0104
(reachable panic in CRL parsing)
- Add advisory ignore for the legacy `rustls-webpki` 0.101.7 copy pinned
to the aws-smithy/rustls 0.21 chain (same chain already exempted for
RUSTSEC-2026-0098/0099)

Fixes the `deny` CI job failure seen in #3325.

## Test plan

- [x] `cargo deny check advisories` passes locally

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-authored-by: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Cargo.lock

@@ -6980,7 +6980,7 @@ dependencies = [
  "once_cell",
  "ring",
  "rustls-pki-types",
- "rustls-webpki 0.103.10",
+ "rustls-webpki 0.103.13",
  "subtle",
  "zeroize",
 ]
@@ -7028,9 +7028,9 @@ dependencies = [
 
 [[package]]
 name = "rustls-webpki"
-version = "0.103.10"
+version = "0.103.13"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "df33b2b81ac578cabaf06b89b0631153a3f416b0a886e8a7a1707fb51abbd1ef"
+checksum = "61c429a8649f110dddef65e2a5ad240f747e85f7758a6bccc7e5777bd33f756e"
 dependencies = [
  "aws-lc-rs",
  "ring",

deny.toml

@@ -83,6 +83,12 @@ ignore = [
     # https://rustsec.org/advisories/RUSTSEC-2026-0099
     { id = "RUSTSEC-2026-0098", reason = "only affects rustls-webpki 0.101 from legacy aws-smithy/rustls 0.21 chain" },
     { id = "RUSTSEC-2026-0099", reason = "only affects rustls-webpki 0.101 from legacy aws-smithy/rustls 0.21 chain" },
+
+    # rustls-webpki 0.101.7: reachable panic in CRL parsing. Same legacy
+    # rustls 0.21 chain from aws-smithy-http-client as above. The 0.103 line
+    # we actively use is upgraded to 0.103.13 which contains the fix.
+    # https://rustsec.org/advisories/RUSTSEC-2026-0104
+    { id = "RUSTSEC-2026-0104", reason = "only affects rustls-webpki 0.101 from legacy aws-smithy/rustls 0.21 chain" },
 ]
 
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