Upgrade baseline curl to 8.1.1 (#160)

* Upgrade baseline curl to 8.1.1

New curl version includes bugfixes, new options but mainly websocket
support which was long requested in curl impersonate. Upstream curl
reworked a lot of their http2 code which necessitated a lot of changes
on our side as well.

* Fix build on mac due to bad header priorities

On macos, clang gives priority to /usr/local/include
over locations specified with -isystem for some unknown reason. In turn
this causes clang to use the system's openssl, which conflicts with
curl-impersonate's boringssl headers.
To prevent that, disable curl's automatic conversion of -I flags to
-isystem.

* Upgrade zlib version

* Upgrade GitHub Mac runner to macos-12

* Upgrade nghttp2 version to 1.56.0

curl-8.1.1 uses an nghttp2 function that only exists in newer versions
of nghttp2.

chrome/curl_safari15_3

@@ -15,6 +15,6 @@ dir=${0%/*}
     -H 'Accept-Language: en-us' \
     -H 'Accept-Encoding: gzip, deflate, br' \
     --http2 --false-start --compressed \
-    --tlsv1.0 --no-npn --no-tls-session-ticket \
+    --tlsv1.0 --no-tls-session-ticket \
     --http2-pseudo-headers-order 'mspa' \
     "$@"