Bump httpx from 0.18.2 to 0.23.0 (#29)

Bumps [httpx](https://github.com/encode/httpx) from 0.18.2 to 0.23.0.
- [Release notes](https://github.com/encode/httpx/releases)
- [Changelog](https://github.com/encode/httpx/blob/master/CHANGELOG.md)
- [Commits](encode/httpx@0.18.2...0.23.0)

---
updated-dependencies:
- dependency-name: httpx
  dependency-type: direct:production
...

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Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Author: dependabot[bot]

requirements.txt

@@ -1,3 +1,3 @@
 pytest==6.2.4
-httpx==0.18.2
+httpx==0.23.0
 rdflib==5.0.0

setup.cfg

@@ -21,7 +21,7 @@ package_dir =
 packages = find:
 python_requires = >=3.7
 install_requires =
-    httpx==0.18.2
+    httpx==0.23.0
     rdflib==5.0.0
 
 [options.packages.find]