lambda-http - disable default features of lambda-runtime

[nstilt1]

📬 Issue #, if available:
Fixes #1092
✍️ Description of changes:
Removes default dependencies of lambda_runtime within lambda_http crate's Cargo.toml.
🔏 By submitting this pull request

• I confirm that I've ran cargo +nightly fmt.
• I confirm that I've ran cargo clippy --fix.
• I confirm that I've made a best effort attempt to update all relevant documentation.
• I confirm that my contribution is made under the terms of the Apache 2.0 license.

[jlizen]

Thanks for the contribution! See this comment for an explanation of not considering this semver breakage.

I'm not sure whether our next release will also be a -rcor not. We will preserve this change for our next non-release-candidate release as well. But, if next release is a -rc, you would need to explicitly depend on the -rc version in order to get cargo to resolve a version that has this change.

(And of course, before our next release, you can always specify the git dependency, if you are building with network access: https://doc.rust-lang.org/cargo/reference/specifying-dependencies.html#specifying-dependencies-from-git-repositories)