Allow IPv6 CIDR notation in `no_proxy`

Merged
MB
4mo ago
+6-1

no_proxy=fe80::/10 (or any IPv6 CIDR) crashed Client() construction because get_environment_proxies() bracketed the whole string including the CIDR suffix, producing the invalid URL pattern "all://[fe80::/10]". Bracket only the address portion and append the suffix outside the brackets.

Closes #899.

Upstream: https://github.com/encode/httpx/issues/3574