Bump httptools from 0.4.0 to 0.6.1

Bumps [httptools](https://github.com/MagicStack/httptools) from 0.4.0 to 0.6.1.
- [Release notes](https://github.com/MagicStack/httptools/releases)
- [Commits](MagicStack/httptools@v0.4.0...v0.6.1)

---
updated-dependencies:
- dependency-name: httptools
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <[email protected]>

requirements.txt

@@ -19,7 +19,7 @@ google-auth==2.9.1; python_version >= "3.7" and python_full_version < "3.0.0" or
 googleapis-common-protos==1.56.4; python_version >= "3.7"
 h11==0.13.0; python_version >= "3.7"
 httplib2==0.20.4; python_version >= "3.7" and python_full_version < "3.0.0" or python_full_version >= "3.4.0" and python_version >= "3.7"
-httptools==0.4.0; python_version >= "3.7" and python_full_version >= "3.5.0"
+httptools==0.6.1; python_version >= "3.7" and python_full_version >= "3.5.0"
 idna==3.3; python_full_version >= "3.6.2" and python_version >= "3.7" and python_version < "4" and (python_version >= "3.6" and python_full_version < "3.0.0" or python_full_version >= "3.4.0" and python_version >= "3.6")
 itsdangerous==2.1.2; python_version >= "3.7"
 jinja2==3.1.2; python_version >= "3.7"