Pending RELEASE-NOTES for the upcoming release

This is work in progress and will change before the release goes public on 14th of April 2021.

Changes:

Bugfixes:

• file: support GETing directories again
• h2: allow 100 streams by default
• hostip: fix builds that disable all asynchronous DNS
• http_proxy: only loop on 407 + close if we have credentials
• libssh: get rid of PATH_MAX
• ngtcp2+gnutls: clear credentials when freed
• openssl: fix CURLOPT_SSLCERT_BLOB without CURLOPT_SSLCERT_KEY
• TLS: fix HTTP/2 selection
• tool_progress: fix progress meter final update in parallel mode
• typecheck-gcc: make the ssl-ctx-cb check use SSL_CTX pointers

Contributors:

Benbuck Nason, Cesar Eduardo Barros, Cherish98 on github, Christian Schmitz, Daniel Kurečka, Daniel Stenberg, Emil Engler, Gilles Vollant, Kenneth Davidson, locpyl-tidnyd on github, Luke Granger-Brown, Ray Satiro, romamik om github, Viktor Szakats,