PyPI readme: fix screenshot links & trim changelog (#2522)

Co-authored-by: Tom Christie <tom@tomchristie.com>

pyproject.toml

@@ -77,5 +77,16 @@ content-type = "text/markdown"
 [[tool.hatch.metadata.hooks.fancy-pypi-readme.fragments]]
 path = "README.md"
 
+[[tool.hatch.metadata.hooks.fancy-pypi-readme.fragments]]
+text = "\n## Release Information\n\n"
+
 [[tool.hatch.metadata.hooks.fancy-pypi-readme.fragments]]
 path = "CHANGELOG.md"
+pattern = "\n(###.+?\n)## "
+
+[[tool.hatch.metadata.hooks.fancy-pypi-readme.fragments]]
+text = "\n---\n\n[Full changelog](https://github.com/encode/httpx/blob/master/CHANGELOG.md)\n"
+
+[[tool.hatch.metadata.hooks.fancy-pypi-readme.substitutions]]
+pattern = 'src="(docs/img/.*?)"'
+replacement = 'src="https://raw.githubusercontent.com/encode/httpx/master/\1"'