Bump sha2 from 0.10.7 to 0.10.8 in /packer

Bumps [sha2](https://github.com/RustCrypto/hashes) from 0.10.7 to 0.10.8.
- [Commits](RustCrypto/hashes@sha2-v0.10.7...sha2-v0.10.8)

---
updated-dependencies:
- dependency-name: sha2
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

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

packer/Cargo.toml

@@ -16,7 +16,7 @@ tar = "0.4.39"
 serde = { version = "^1", features = ["derive"] }
 serde_yaml = "0.9.25"
 anyhow = "^1"
-sha2 = "0.10.7"
+sha2 = "0.10.8"
 data-encoding = "^2"
 serde_json = "^1"
 rayon = "^1.8"